Notes on Sumatra

Across the Straits of Malacca from the Malay Peninsula lies the island of Sumatra, part of Netherlands India. At its nearest point it is only 35 miles from the Peninsula, and, at its northern end, it is no more than 100 miles away. Small trading stations on the coast had been occupied by both the British and the Dutch, during the past one hundred years, but only within the last fifty years has any considerable extent of the country been opened up. About the middle of last century a tobacco company—afterwards to become the great Deli Maatschappij—took up a large tract of land; and their headquarters, Medan, became the site of a fine town, and also the political and commercial capital of North-east Sumatra. Other tobacco companies followed in their wake, and subsequently large areas were planted with rubber.

Reports came to the Federated Malay States of the excellence of their hospital system, and of the low death rates of the labour forces employed on estates in Sumatra. In view of the difficulties we had met with in controlling malaria in the Federated Malay States and the high mortality from it among our labour forces, I was anxious to visit Sumatra in order to learn how it was controlled there. I also desired to ascertain if malaria was distributed as it was in the Federated Malay States, or as in Italy. Mr Rainnie, the representative of Messrs Harrisons and Crossfield, Ltd., in the Federated Malay States, kindly gave me a letter of introduction to Mr Mathewson, their representative in Medan, and through his kindness I was able to see a considerable part of the country, and meet those who gave me much help.

My stay in Sumatra was, however, of a very limited duration, and that the reader may form a proper estimate of the value of my views and observations, I propose to record what I saw much in the form in which it exists in my journal. In this way the value of any statements made may be gauged; and at the same time observations may be recorded, the full significance of which may be grasped by others, although perhaps appreciated only in part by myself.


Travel to Sumatra



Leaving Penang about midday on the 3rd of March 1913, the steamer sailed for Belawan, the port for Medan, at a leisurely pace; for it would be impossible to cross the bar at the mouth of the river until about 8 a.m. on the following morning. The coast is low-lying as in many parts of the Federated Malay States, and covered by mangrove forest. The rise and fall of the tide here is 7 feet, only half of what it is at Port Swettenham. On an island two or three miles from the mouth of the river, the small town of Belawan forms the terminus of the railway to Medan. The construction of this port, as at Port Swettenham, and the building of the bridge connecting the island with the mainland, had been the occasion for a serious outbreak of malaria; and the reputation of the place is still such that all Europeans connected with the port live in Medan, coming down to Belawan by the first train in the morning, and returning by the last in the afternoon.

I was hardly surprised at its reputation. The town had been built on a mangrove swamp. The site had been made up with earth brought down by rail, and, owing to the great expense of this, the minimum amount of the mangrove swamp had been reclaimed. Although a small part of the native portion of the town had a bund round it, no attempt had been made to reclaim a large portion of the swamp by bunding and draining, as at Port Swettenham, and the mangrove grew to within a couple of chains (132 feet) of the houses. With no inducement to expand, the town consists simply of a narrow strip of raised land on the edge of the island, and at its widest part is not 10 chains across. The whole town is well within the malaria radius of the swamp.

In the brief stay I made at the port, it was impossible for me to examine the children; but, as will be recorded later, on a visit to a somewhat similar place on the edge of mangrove, I found a percentage of the children with enlarged spleen. There is good reason to believe, therefore, that Belawan deserves the reputation it has.



The distance from Belawan to Medan, some 20 miles, occupied an hour in the train. After leaving the station at 1 p.m. at Belawan, the train ran through the mangrove forest which covered the island, and soon reached the bridge that connects the island with the mainland. Over this the train ran at about 3 miles an hour; for, I understand, the piles of the bridge are floating in the mud; no solid bottom could be reached. The remaining part of the journey calls for no special comment. It was through kampongs, full of fine old fruit trees, and full, too, of the weeds and lalang so characteristic of native cultivation.

So far as could be ascertained from the train, the country was flat, like the alluvial flats of the Peninsula; but in reality it was not so; and Medan stands 50 feet above the level of the sea. Through Medan a small river flows, and it has cut a channel with almost vertical sides 15 to 20 feet below the general level of the ground. The current of the river at Medan is 4 or 6 miles an hour in dry weather. No water stands in the roadside ditches in and around the town. Evidently the natural drainage of this part of the country is excellent, and the ground-water is low. During my stay at Medan, I noted a general freedom from mosquitoes, and greater dryness in the air, than in the Federated Malay States. In fact this was a very pleasant feature of Medan. The town is well laid out and well looked after.

Calling on Mr Mathewson, I explained the reasons for my visit, and he arranged for me to see a considerable tract of the country. He also introduced me to Mr Van Tyn, the chief administrator of the Deli Maatschappij, who in many ways gave me assistance.


Tandjong Kassau estate


5th March: Medan to Tandjong Kassau

From Medan to Tandjong Kassau is 64 miles; and the road runs, roughly speaking, parallel with the sea, and from 10 to 20 miles inland. On leaving Medan the scenery was as different as possible from that of the Federated Malay States. In the Federated Malay States when the land is not under cultivation, or under lalang following the abandonment of the old tapioca clearings, it is covered by jungle, and the road is only a narrow lane cut through dense forest. But in this portion of Sumatra practically the whole country has been cleared of jungle; and on the T. Kassau road I did not see jungle until about 45 miles out of Medan.

The reason for this wholesale clearance is that a second crop of tobacco cannot be taken from the land until it has rested seven years. So the tobacco estates usually consist of 8000 acres, 1000 of which are cultivated each year. After the tobacco crop, a crop of rice is taken the following year, and the remaining six-eighths of the estate is allowed to spring up in secondary growth. A comparatively small area of cultivation of this kind is, therefore, responsible for the destruction of a large area of jungle; and country so treated is much more open than the Federated Malay States, where cultivation is on more economical lines.

On the left as we drove along, the eye traced the land gradually rising till it ran into the great range, some 4000 to 5000 feet high, which forms a backbone to Sumatra. On the cultivated portions of the estates great sheds covered by attaps (palm leaves) were prominent objects in the landscape. In these, the tobacco leaves receive a preliminary drying before being taken to the fermenting sheds at the headquarters of the estate. The only other thing that caught the eye was a clump of tall casuarinas, marking the headquarters of the estate.

We crossed many rivers, all of which were at least 6 feet and some 20 feet below the average ground level. The ground appeared on the whole to be level, only undulating where it dipped into, and then rose out of, what seemed an old river track. The soil in the sides of these old tracks was red; and that in the bottom grey. The general groundwater level, except in these tracks, must have been 25 to 30 feet below the surface. At the time of my visit the ground was very dry; and all the little streams contained dirty looking water. Often the colour was dirty white, like that in a road puddle; and before I knew anything of their actual inhabitants it occurred to me they were ideal breeding places for A. rossii.

In all the 64 miles I noted only one mile where a river—the Sungei Ular—had spread itself out as a swamp. Through the swamp the road ran on an embankment; and the land was too low and swampy for cultivation. When at last we came to the virgin jungle, it was seen that the land was dry, not swampy like the alluvial plains of the Federated Malay States, and that the jungle trees were of particularly fine growth, a happy omen for rubber in Sumatra when the trees have reached maturity.


A healthy estate: A. maculatus absent

My object in visiting this estate was to see how far it corresponded with a hill estate in the Federated Malay States in physical characters, and if so, whether or not malaria was present. On arrival, Mr Blick, the general manager of the Tandjong Rubber Company, kindly took me to the hospital, which is under the charge of Doctors Manchaunp and Van Wyl.

The hospital consists of a number of buildings connected by corridors. Each ward is 70 feet long by 22 feet wide, and has accommodation for forty patients. At one corner there is a room for a dresser. The walls are brick, the floors cement, and down the centre runs a shallow drain. There is no verandah. The windows are covered by mosquito-proof screening fixed so that it cannot be removed. On the inside the screening is protected by ordinary half-inch mesh iron-wire netting. The disadvantage of this is that the screening cannot be easily cleaned. The jack-roof was also screened. So were the double doors, where, however, the screening had been partially destroyed by rust, evidently from water used in washing the floors. I was informed that in the new wards there was not to be screening above the wall plate under the eaves, or on the jack-roof. The experience in Panama is that screening is required especially under the eaves.

There is separate ward accommodation for dysentery. In the latrine the excreta are deposited in a dry cement trough, which at frequent intervals is washed down with a disinfectant (? Jeyes’ fluid) into a large pit. The pit is emptied once a month.

The latrine was free from objectionable smell, and no flies were present. The dispensary was well furnished. The operating room was well provided with instruments; and there was a room for microscopic examination of blood, and other material from the wards.

The work of the medical officers is almost entirely confined to the hospital. Although visiting the estates from time to time to inspect the sanitary arrangements and to attend sick Europeans, it has been found most satisfactory to send sick coolies to properly equipped central hospitals rather than call the medical officers to see the coolies on the estates. Coolies are allowed to be one day off work, and are given simple treatment if they complain, but do not wish to go to hospital. If, however, not fit for work on the second day, they are sent to the hospital in a spring bullock-cart. Like most Sumatra hospitals, this is a combined hospital, and received patients from ten estates, the farthest of which is 18 miles away. Three of these estates have not contributed to the cost of building the hospital, and are called Outside Estates in Table 6.1, which shows the number of coolies in hospital on 5th March 1913.

Table 6.1: Patient distribution in the hospital at Tandjong Kassau, as of March 5th 1913
Patient affiliation Number
Outside (non-contributing) estates 50
New coolies under medical observation 76
Contributing estates 445
Total 571

All new coolies are passed through hospital, and subjected to thymol treatment for ankylostomiasis. The 445 coolies represent the sick from a labour force of 8596 on the combined estates. In practice the estates provide 5 beds per 100 of the labour force, and this is usually found to be ample.

During 1912 there were 6025 admissions to the hospital from all causes, including the admissions of new coolies for thymol treatment. For malaria there were 611 admissions, or a rate of 71 per 1000 of the labour force; that is, 5 per 1000 less than the malaria rate in Panama in 1913, and 39 less than the rate in Panama in 1912. The death rate of the whole group of estates was 33.8 per 1000.

For Tandjong Kassau Estate alone in 1912, the malaria admission rate was 187, and the death rate 42 per 1000. This and other estate death rates in Sumatra refer, however, only to the indentured labourers. The children are treated usually by native doctors; and Mr Blick tells me the infantile mortality is high. The children are only sent to hospital if the mother wishes this; and their deaths are not taken into account in estimating the death rate of the labour force.

Of eighteen Europeans, the staff of the Tandjong Estates, only one has suffered from malaria in the past eighteen months. Tandjong Kassau Estate is undulating, and in the Federated Malay States would in 99 cases out of 100 be intensely malarious. Mr Blick’s bungalow is situated at the junction of two ravines; yet he and his family and servants do not suffer at all from the disease, and all look in good health.

Table 6.2: Spleen rates of children on the Tandjong Kassau Estate
Coolie quarters Number of children examined Number with enlarged spleen
New lines 12 1
Old lines 41 1
Total 53 2

The children on the estate are equally free, as will be seen from Table 6.2; the overall spleen rate is 3.9 percent. The spleen of the single positive child in the new lines was just palpable, and I could get no history of the child having had fever. The positive child in the old lines had arrived only two months before from Java. Its mother said it had had fever before arrival. All the other children looked in excellent health. There can be no doubt this estate is free from malaria, except what is imported.

Three photographs taken at Toentoengan estate, showing
                coolie housings, a ravine, and adjoining djungle.
Figure 6.1: Toentoengan estate, Sumatra. A: Coolie lines on ridge. B: A ravine. C: Jungle at boundary of the estate, close to coolie lines.


In the stables close to Mr Blick’s house numerous A. rossii were captured, but no other species. In the ravine below there were a number of drains the water of which ran sluggishly. In some drains were leaves and algae; and the water had a rather slimy look. Many larvae were taken from the sides of these drains. Most of them died on the journey back to Medan; but a few ultimately hatched out as A. rossii. Similarly in a ravine near the new lines, larvae in abundance were found among the leaves at the side of the drain. The water here was also slimy, and rather dirty looking. The larvae were easily captured. Through a flat part of the estate to the hospital runs a stream, about 10 feet wide by 3 feet deep. At its sides I captured one pupa and several larvae. One of the latter had the white mark on its neck indicative of A. kochii; but unfortunately it failed to hatch out. I noted many small pieces of vegetable matter and debris in the stream.

My conclusions from this visit were— (1)that the estate was free from malaria contracted on the estate; (2)that this was due to the absence of A. maculatus from the ravines; (3)that this freedom from A. maculatus might be due (a) to the constitution of the water being unsuitable to it, or (b) to A. maculatus not occurring in Sumatra.


Toentoengan estate: a typical hill land estate, yet free from malaria

On March 6th, Mr van Tyn called sharp at 7 a.m. and drove me in his car inland to Toentoengan Estate, the highest estate belonging to the Deli Maatschappij. It is between 200 and 300 feet above the sea level. On arrival at the estate it was at once apparent that in every way it could be classed as a hill estate, and in Malay would be, except by the very rarest good fortune, intensely malarious.

From the road the path runs for about half a mile on the level, but surrounded on all sides by the curious bank-like hills seen in Sumatra. On the left was jungle, the boundary of the estate. In the flat portion of the estate was a small stream and a number of drains; in the stream no larvae were found; nor was my search in the drains more fruitful until I reached their upper ends. Here, especially in one drain, where there was grass, I took many Culex larvae, but no Anopheles. Climbing over a ridge, I reached a ravine which came out of the jungle only 100 yards away. The water in the drains was beautifully clear, quite unlike what had been seen in the lower portions of the country. I should mention the soil of this estate was black, not the usual red. In the masses of algae, Culex larvae and egg-rafts were abundant; but the most careful search did not discover a single Anopheles. In some of the drains there was considerable current.

Proceeding to the next ridge, I had a magnificent view of the block of the estate under cultivation, and of the country in general. But of most interest to me was a deep ravine, with many side branches and steep sides scored in the earth a full hundred feet. The sides were so steep that the path down consisted of steps. If anything was to be called a ravine this deserved the name, and it was with some haste I descended. But here, as in the previous ravine, no Anopheles could be found. Of Culex there was abundance, especially in the algae. And I noted particularly that these mosquitoes were present in the algae of the various streams, despite the existence of shoals of small fish. When I returned to the main road, my man reported he had not caught any adult Anopheles in the houses.

The labour force consisted last year of 1200 coolies, of whom 1000 were indentured. Of this force, nine died in hospital, and one on the estate, which gives a death rate of 8.3 per 1000. From a consideration of these figures, from my failure to obtain larvae in the streams and the adult insects in the lines, it is apparent the health of this labour force is infinitely better than it would be on a correspondingly hilly estate in the Federated Malay States, and the conclusion is suggested that this is due to the absence of malaria.


The labour system in Sumatra

The labour system in Sumatra is exactly the reverse of what it is in the Federated Malay States. In Sumatra practically nothing but indentured labour is employed. The composition of the labour force preferred by managers is half Chinese and half Javanese. The former being more industrious, set the standard of work. But to trust to free Chinese labour alone would be to court disaster. For the Chinese guilds, or trade unions, are well organized; and with the demand for labour being greater than the supply, they could easily afford to, easily could, and certainly would ruin an estate that refused their demands. The coolies receive their full wages in cash, and they feed themselves. But the estate provides a shop where rice is issued at a price fixed by the Controller of Labour.

The Javanese are recruited in Java; the Chinese locally. There is practically no absconding, since no coolie can obtain employment without establishing his identity; and, under the Dutch system, he is required to register in the district in which he resides, or in any new one to which he removes. One of the advantages of indentured labour is that the manager of an estate can count on having a definite labour force at the season specially suitable for planting out the tobacco plant, or for gathering in the leaf at the moment of maturity. With such a delicate plant, to miss a spell of dry or wet weather is to miss the season, and lose a year’s crop. These times would be the Chinaman’s opportunities for squeezing the estate. Under the circumstances one can understand why the Sumatra planter is a strong advocate of the indentured system. The labour is under the control of a government department; and, as will be seen, under it the coolies enjoy a degree of health and prosperity unapproached by anything they have ever enjoyed or ever are likely to enjoy elsewhere.


Deli Maatschappij hospital at Medan

This, the largest hospital belonging to the Deli Maatschappij, contains about 600 beds. Dr Römer, the chief medical officer, kindly showed me over it. Most of the buildings have been up many years; nevertheless, the wards are large and freely ventilated through the lattice-work sides. There are no verandahs; the floors are of cement; the roof of shingles. The beds are either plain planks or wire mattresses. The latter are disliked by the coolies, and are not used unless the other beds are occupied. There is an excellent dispensary, and an up-to-date operating room. An examination room, fitted with X-ray and other apparatus, enables the fullest possible examination to be made in obscure cases. The latrines consist of troughs full of disinfectant. These and all the sewage from the hospital drains are run off into the river once in the twenty-four hours.

In his office the medical officer has a fine medical library. Careful records are kept, and the Annual Report of about fifteen closely written pages deals with each disease in detail, and is full of statistical tables and charts. Dr Römer was kind enough to allow me to peruse his report and make extracts; and since my return to the Federated Malay States Dr De Jong has kindly given me some additional information. It is a most interesting record of the health of a great tropical labour force, whose diseases have been studied with scientific care (see Table 6.3); and it is a record of which any hospital might be proud.

Table 6.3: Annual case statistics of the Deli Maatschappij Hospital at Medan, 1900–1911
Year Labour force Admissions Death reate of hospital (%) Death rate per 1000 of labour force
1900–01 8,766 3,846 11.4 50
1901–02 8,832 3,320 7.4 27
1902–03 10,459 4,316 6.0 25
1903–04 9,940 4,812 4.4 21
1904–05 9,294 4,287 4.8 20
1905–06 9,796 4,525 2.4 11
1906–07 10,633 4,643 3.5 15
1907–08 11,009 5,734 3.0 16
1908–09 9,866 5,407 2.6 14
1909–10 9,916 4,291 1.9 9
1910–11 10,290 4,289 2.6 12


New coolies are not admitted to the hospital for thymol treatment, as is done at Tandjong Kassau Hospital; and in 1910–11 only twenty-eight cases of ankylostomiasis were admitted, of which one died. In addition, 219 cases of anaemia were admitted, with one death. Even assuming that all the anaemia cases were due to the ankylostome, it is evident that the worm does little harm to the labour force. Whatever the truth may be as regards the Javanese coolie in Sumatra, I have never been able to accept the view that the Tamil coolie in the Federated Malay States was decimated, or even seriously handicapped, by this worm. My reason for thinking the importance of the worm in this country to have been exaggerated, is the fact that it is present uniformly in 90 percent of all our labour forces, whether healthy or unhealthy; and that the death rates vary with the spleen rates, while the worm is a constant.

There are reasons, however, quite apart from the worm, why the use of the latrines on estates should be extended; and I am glad to say that is actually taking place. The real difficulty, and not a small one, is to get the coolie to use them.



Table 6.4: Malaria admissions and deaths at Medan Hospital in 1910–1911
Malaria form Admissions Deaths
tertian 200 3
quartan 24 1
tropica 30 0
Total 254 4

No less significant are the figures for malaria. The numbers shown in Table 6.4 give an admission rate for malaria of only 24 per 1000. In 1911–12 the admissions for malaria amounted to only 220. The rate of twenty-four is just less than one-third of the admission rate for malaria in Panama for the year 1913. In Panama the result is attained, as we shall see, by organization and infinite care; in Sumatra an even greater freedom from malaria exists, simply because over large tracts of the country malaria is not endemic. What a different picture there would be in Medan Hospital were the disease endemic on the Deli Maatschappij Estates.



Table 6.5: Causes of dysentery at Medan Hospital in 1910–1912
Cause of dysentry 1910–11 1911–12
Amoeba1 54 44
Bacillus Shiga2 17 14
Bacillus Strong2 5 0
Bacillus Flexner2 0 5
Bacillus Y2 7 19
No bacterial diagnosis 76 65
Total 159 147
now named Entamoeba histolytica
now classified as Shigella species

Working along with the Medical Institute, it has been possible to classify the dysentery cases according to their causes. The numbers listed in Table 6.5 do not represent a large amount of dysentery in so large a native labour force; but it takes a considerable toll in lives. Unfortunately there is nothing to indicate a prospect of dysentery disappearing, or being even materially reduced in amount, as is shown in Table 6.6.

Most sanitarians nowadays agree with Colonel W. J. Buchanan24 that the water-borne theory of dysentery and typhoid has long broken down, and cannot account for the persistence of a few cases of dysentery or typhoid. When these diseases are conveyed by water, the outburst is sudden, severe, and widespread, and is quickly stopped on changing the water. Such outbreaks one sees when an army is in the field. But to think of dysentery purely as a water-borne infection is to miss the fact that there are often other causes really responsible for the outbreak, and that the removal of these causes will remove the outbreak.

Table 6.6: Admissions and deaths due to dysentery at Medan Hospital
Year Cases Deaths
1900–01 163 103
1901–02 119 59
1902–03 139 82
1903–04 115 61
1904–05 74 44
1905–06 50 25
1906–07 86 37
1907–08 117 95
1908–09 133 55
1909–10 112 21
1910–11 159 58
1911–12 147 30

Principal Diseases

Table 6.7 shows some of the principal diseases that affected the labour force in 1910–11. It will be noted that dangerous infectious diseases like cholera, typhoid, smallpox, and cerebrospinal meningitis appeared, and their presence easily accounts for the rise of the death rate from 9 per 1000 in 1909–10 to 12 per 1000 in 1910–11. That the death rate only reached 12 in the presence of these diseases seems to me to indicate how rapidly the medical staff got them under control.

Table 6.7: Principal diseases at Medan Hospital in 1910–1911
Diseases Admissions Deaths
Malaria 250 3
Dysentery 159 58
Bowel diseases 306 86
Cholera 48 18
Typhoid 20 5
Smallpox 40 11
Cerebrospinal meningitis 43 41
Ankylostomiasis 57 2
Anaemia 155 1
Pulmonary tuberculosis 36 14
Beri-beri 66 7
Pneumonia, croupous 142 40
Pneumonia, catarrhal 142  
Broncho-pneumonia 133 5
Venereal diseases 268 3
Nephritis (acute and chronic) 20 9
Surgical diseases 689 11

The Medical Institute

This fine institute belongs to, and is supported by, the estates in N.E. Sumatra. It is much superior to what the London School of Tropical Medicine was before the recent extensions. The institute carries out all complicated diagnostic work for the estates. It also makes immunizing serum for human and cattle diseases, and generally is of assistance to the estates in all affairs where exact scientific observation and work are required. Not only does it justify its existence by this routine work alone, but Dr Kuenen has found time to carry out original research. Dr Vorvoart will shortly join him as assistant director. At the time of my visit Mr Swellengrebel, protozoologist of the Amsterdam School of Tropical Medicine, who had been studying plague in Java on behalf of his school, was working in the laboratory. To Dr Kuenen and these other gentlemen I was indebted for much assistance, as will be seen from the following narrative, and not less for placing a room in his laboratory at my disposal.

While examining an A. rossii that afternoon I noticed a “tick” or “mite” on it. It was not red like those that I had seen on A. umbrosus, and that had been described by Dr Strickland, but pale straw coloured. It was seen by Dr Kuenen and Mr Swellengrebel, but unfortunately it dropped on to the desk when we moved it, and we could not find it again. What it was could not be ascertained.


Bekioen and Bandar Talu: hill land estates

Photograph showing four unidentified men standing in a ravine
              on Bandar Talu estate, Sumatra
Figure 6.2: A ravine in Bandar Talu Estate, Sumatra


March 7th. At 6 a.m. Dr Kuenen and Mr Swellengrebel called, and we started for Bekioen, where an outbreak of malaria had occurred last year. The road lay roughly in a north-west direction until we reached the town of Banjai on the Sungei Bingai. The town is clean, and the river bed lies some 20 feet below. Then the road struck more inland towards the main range. On this road again it was many miles before we saw jungle, but shortly before reaching our first stop we ran through a new clearing some 10 chains wide on each side of the road. This was part of Bekioen Estate. I was informed later on that no malaria existed, nor had existed, among the labour force on this clearing. Such would not have been the case in the Federated Malay States. At 7 a.m. we turned off the road into one of the clumps of casuarina trees of which I have spoken, and drew up at Dr Hauzinga’s house, one of several occupied by the European staff of the estate. Each house has its garden of 2 or 3 acres. Dotted about, in no apparent order, and quite close to each other, they are nevertheless isolated by trees and hedges, while all together they form a delightful oasis in the wilderness of tobacco fields and temporarily abandoned land. Substantially built, furnished much more in European than Eastern fashion, and surrounded by beautiful gardens, these houses suggest a home more than anything to be seen in the Federated Malay States.

One of the great causes which invalids both men and women from the tropics, is what is called neurasthenia. It may be defined as a condition of the nervous system supersensitive to the impressions it receives; when, in fact, everything is a worry. It comes from overwork, want of rest, and often follows other illnesses. Common in temperate climates, it is even commoner in the tropics; and I cannot help feeling that were the English to make their houses and quarters in the tropics as homelike as the Dutch do, there would be less neurasthenia.


Bandar Talu

After breakfast Dr Hauzinga took us to Mr Prins’ estate, which is called “Bandar Talu.” It is under rubber about two years old. The estate is much cut up by ravines, which are now being cleared of “blukar,” i.e. small jungle. The manager’s house and three sets of coolie lines are situated close to ravines. Although being cleared up, the water in the ravines had not yet been fully exposed, and we searched only in the more open places in two streams. Both streams were running very sluggishly. In the grass at the sides of the first stream many small larvae were taken. In the second many large black larvae were found. They suggested A. sinensis or A. barbirostris. Unfortunately they died; the long motor-car journey drowned them.

Dr Hauzinga said there had been as many as seven cases of malaria in one month last year from the estate, i.e. less than 5 percent per month of the labour force. The total number of deaths in the year was, however, only two. Both deaths were from dysentery. The water-supply on the estate was considered bad. Table 6.8 shows that the labour force almost trebled in the year. On an examination of the children (the number examined unrecorded, but could not have been many), I found none with spleen enlarged.

Table 6.8: Workforce on Bandar Talu Estate, 1912
  Number of coolies Deaths
January 63 -
February 79 -
March 130 -
April 131 -
May 147 -
June 150 1
July 174 1
August 173 -
September 172 -
October 173 -
November 173 -
December 173 -

Mr Le Prins says there are many “Agas” (Ceratopogon)—miscalled “sandflies” in Malaya). My man was unable to catch any Anopheles.


Sumatra’s profile

Bandar Talu Estate is 600 feet above sea level, and from one point a magnificent view of the country is obtained. I might call it a profile view. At first slowly, and then more quickly, the line gradually rises from sea level until it ends almost vertically in a smoking crater nearly 5000 feet up. The air was extraordinarily clear that day, and every detail of a gorge below us was visible.

The gorges of Sumatra form a very striking feature of the scenery. The land, except when we have actually reached the main range at an elevation of nearly 2000 feet, appears to the eye to be level as we travel along the roads. Then suddenly, almost without a warning, a chasm opens, in the bottom of which a river is dashing down among great and small boulders. These chasms are river valleys; but the edges of the valleys are not worn away, as one would expect in a country with so heavy a rainfall as North-east Sumatra. The edge is more like the edge of a canyon, which cuts through the tableland or “mesa” of the arid regions of America, than anything I have seen. Yet in this part of Sumatra the land consists simply of volcanic ash, not much compressed, with a good sprinkling of volcanic boulders. The explanation of the sharp edges is perhaps to be found in the gluey nature of the soil, formed from this ash when wet. Friable enough when dry, it sticks like glue when wet. In Hawaii, which is similarly volcanic and with a similar soil, I found walking on the wet red earth very difficult and fatiguing. Every few minutes it was necessary to stop to knock off the masses of earth which adhered to my boots. As we shall see later, this same soil is found in Panama, and its peculiar character has led to very important modifications in their anti-malarial methods.25


Kuala Namoe Estate—formerly malarious

Returning from Bekioen in time for tiffin in Medan, I set off immediately afterwards for Kuala Namoe, about 14 miles out, accompanied by Dr Vorvoart. Two years ago Dr Vorvoart was medical officer to this estate, and at that time there was a considerable amount of malaria. On the way, we picked up Dr Schüffner, whose name is familiar to every student of tropical medicine as the discoverer of the stippling of the blood corpuscle infected by certain forms of the malarial parasite. Dr Schüffner took us to a number of pools in borrow-pits, but we found no Anopheles. The water in the pools was dirty, and had any mosquitoes been obtained I have little doubt they would have been A. rossii. Kuala Namoe Estate may be called flat, and is so as far as the eye can see. About 25 to 30 chains from the lines there is a swamp, caused by the overflow, in wet weather, of a small stream. At the time of my visit the swamp was dry, and the stream was confined to its narrow and rather ill-defined channel. The edges were covered with a heavy growth of grass, and the current in the centre ran about three miles an hour. It struck me at once as an ideal breeding place for A. albirostris. Many larvae were taken, but at the time I left Sumatra they had not hatched out. In the lines, however, my man caught four Anopheles, namely: (1)A. rossii, (2)A. sinensis, (3)A. albirostris. I have no doubt the A. albirostris came from this stream. The estate is now healthy, and an assistant’s bungalow at one time full of malaria is now free from it.


Tandjong Morawa and Rantan Pandjang


Tandjong Morawa

March 8th. Leaving at 6.30 a.m., I motored out to Tandjong Morawa, where Dr Schüffner is medical officer. His house, like the others of the company, is in a beautiful garden on the banks of a considerable river. The hospital, which is close to the house, receives patients from several estates. In his laboratory there is a large room well equipped both with apparatus and books. Dr Schüffner showed me microphotographs of the various Anopheles that he had captured and sent to Dönitz for identification ten or twelve years ago. Dönitz had identified them as A. kochii, A. plumigar (? sinensis), and A. rossii. Dr Schüffner had not done much recent work on mosquitoes, as malaria was not a problem for the estates under his care. He, however, had paid some attention to Rantan Pandjang, where malaria exists, and after seeing the hospital we drove there.

The hospital at Senembah is in nicely laid out grounds. The floors are of cement. All serious cases are treated in mosquito-proof portions of the wards, so that the patients may not be annoyed by the insects. All dysentery cases are treated in a mosquito-proof ward, which, if necessary, is emptied and used for cholera cases. The screening throughout was in good order. The water for the hospital is from a well in the grounds from which it is pumped to a tower.

Dr Schüffner submits all the new coolies to a course of thymol, and I saw the method carried out here on a considerable scale. After the treatment, each patient brings the large enamel vessel with his excreta down to the river, and that morning there were some thirty patients. The vessel is filled with water from the river, and then decanted. This is repeated until all the faeces are washed away, while all worms are left behind. The whole process is carried out quickly by a Chinese coolie. The worms are then examined under the microscope, and classified. The two forms of ankylostome, Ankylostoma duodenale and Necator americanus, male and female, and the various other worms, Ascaris lumbricoides, Trichocephalus dispar, etc., are separated and their numbers are recorded on the patient’s chart. I may add, the river is 15 to 20 feet below the level of the surrounding land.


Rantan Pandjang

We then motored to Rantan Pandjang, an estate about 10 miles from Tandjong Morawa where Dr Schüffner had found much malaria among the natives. For the first part of the road we were on land similar to that with which I was now familiar, namely, red, light yellow, or white soil, with the groundwater 15 to 20 feet below the surface. Then we came to a part which was, from its vegetation, evidently a swamp in wet weather. At that time it was dry, but the groundwater stood only a foot below the surface. No big jungle could be seen, the land being covered by secondary jungle about 30 feet high. A creek along which the road was was tidal, but the water was fresh. In a pool we got several large black larvae, which had frontal tufts like A. sinensis or A. barbirostris.

Continuing for another mile or so, we came to Rantan Pandjang, a considerable village. Dr Schüffner was evidently well known in it, and a welcome visitor. A number of children were at once brought for examination, but he observed one could not be sure the sick were brought, and such an examination was liable to give unduly favourable results.


Method of obtaining children for spleen examination

To overcome this difficulty, I suggested we should make a house-to-house visit to a portion of the village, with children as guides, to those houses in which there were children. I have found this a very effective way of obtaining both information about children, and the children themselves for examination. After talking to some of the older children in a village, they will generally submit to examination, and once they have been examined they usually show great zeal in bringing others for examination. In a very short time a number of children can be attracted, and the examiner has then overcome all his difficulties. In going from house to house, the guides tell you beforehand whether it contains a child or not. Mothers, under these circumstances, rarely deny the existence of a child, and the child rarely resists being brought to the examiner by its own companions. In a few minutes, too, these invaluable small assistants learn to loosen any clothing round the child’s waist that might interfere with the examination, and in a country with many different races they act as able interpreters.

By such means the work can be done with a maximum of speed and minimum of resistance. I would go further, and say that it serves as the best possible introduction a European medical officer can have to a native race, and completely eliminates all chance of error through the examiner seeing only the healthy children. The keenness of the children, their delight in the new game, their intelligent questions, and their desire for information, have made these days for me among the most interesting in my life in the East, and always a delight. It is a great game for all of us. Among adults “slackness” is common; among children it is never seen, unless perhaps when the poor mites are actually suffering from “fever,” and even then it is not invariably present.

In this way we went from house to house until we had examined thirty children. Of these, ten (or 33 percent) had enlarged spleen. One spleen alone was much enlarged, and it was found in the only child that looked ill. We then searched for larvae, but were not only unsuccessful in finding Anopheles, but almost equally so in finding possible breeding places. The weather had been very dry for some time, and the ground was baked hard. Even an extensive rice field was quite dry in holes a foot deep. Ditches 3 to 32 feet deep were also dry, and the water found was only in a few wells about 5 feet deep. In these Culex larvae existed. My man was unable to catch any adult Anophelines. It would be very interesting to visit this place in the wet season, for the spleen rate denoted a considerable prevalence of malaria.

Crossing a branch of the main creek on a doubtful looking bridge, we walked about a mile to a fishing village on the sea, called Bagan Serdang. The houses are built on the ridge of sand which forms the beach. On the sea side the sand runs off into the long mud shore so common in these parts. And on the inland side the land is a mud swamp, drained by tidal creeks.

Of eleven children two had enlarged spleen (18 percent). We could find no Anopheles breeding places.


Summary of findings

Thus in Rantan Pandjang and Bagan Serdang there was clear evidence of endemic malaria, in confirmation of Dr Schüffner’s statement. And with the history of Balawan, before alluded to, there can be little doubt this low-lying part of the coast is malarious, just as it is in the Malay Peninsula. On the most interesting question of all, what the carrier of malaria is, I can throw no light. Undoubtedly Rantan Pandjang is a very favourable place to study it. It is of no small practical importance to determine whether or not A. ludlowi, which breeds in brackish water, is a carrier of malaria.

Major Christophers has found zygotes in the stomach of this mosquito in the Andaman Islands, where malaria appears to be found only along" the sea coast and salt-water inlets. Dr De Vogel of Java has also recorded the presence of mosquitoes in the brackish water of sun-cracked mud on the sea coast associated with severe malaria. The mosquitoes were identified by Theobald as A. rossii, but as this was as long ago as 1908, it may be the mosquito was really A. ludlowi.

My feeling, from what I have seen in the Federated Malay States, is that A. ludlowi can exist without producing malaria, and indeed that malaria will disappear from a place when steps are taken which abolish only A. umbrosus—a proved carrier—yet leave very large numbers of A. ludlowi. The question is one of great importance, and further investigation is required.


The Sumatra highlands

March 9th. An early start was necessary, and at 4.45 a.m. I was called for a cup of coffee, which would make the run in the cold morning air more tolerable. In due course Dr Kuenen, Dr Vorvoart, and Mr Swellengrebel arrived in the car, and we got away with the first glimmer of daylight. It was a splendid road on which we travelled, and had been constructed for military reasons connected with the long-drawn-out Acheen rebellion.

A few miles out from Medan we crossed something that at first glance looked like a railway cutting, about 20 feet deep, only instead of rails there was a masonry or cement channel about 4 feet wide, with small transverse bridges supporting every 20 feet. This is the water supply for Medan, the source of which we were to see farther up the hills. For the first few miles we were in wide, open country, and had a magnificent view of the mountains. The road was rather tortuous, and we kept on the tops of the “mesas.” Although apparently flat, the engine was having collar work all the time, but its 40 horsepower took no notice of the 1 or 2 percent grades.

Suddenly the road began to descend into a valley. The turns were very sharp, and required careful driving; but our driver was an expert. In this valley there is the highest tobacco estate in Sumatra. The road then creeps up a small valley, and crossing a watershed plunges into the gorge of the Sibolangit River. Crossing the river by a bridge, I noticed men collecting stones from the river bed, which are the only quarries they have in North-east Sumatra. All the roads are covered with water-worn pebbles. Near to the sea it is more difficult to get stones, and so many of the roads are unmetalled. From the road we now had a magnificent view of the gorge, and again I was struck by the sharp edge.

Looking back to my visit to the American chasm, and knowing the magnitude of that great work of nature, it may appear absurd to compare this Sumatra gorge with the Grand Canyon, yet to the eye the comparison is by no means absurd. The Grand Canyon is on so great a scale, and the atmosphere is so clear, that the eye fails to realise to the full the 13 miles across, and the 3000 feet drop to the top of the inner gorge, or 5500 feet to the bottom. The Grand Canyon produces its effect, apart from its exquisite colouring, as much through the mental consciousness that it is a mile deep, as through any actual visual realization of the fact. Here in Sumatra the gorge is nearly 1000 feet deep, a depth quite sufficient to impress the eye. Its steep sides clothed with trees were something very different from the canyon in the West; yet having seen the two, I would venture to say that this gorge is one of the most beautiful sights in the world, and a visit to it, something to be treasured in memory.

The road now takes a sharp bend, and above us was the Sibolangit plateau. From its base come the springs that supply Medan with water. Where the water enters is unknown. Probably it has had a very long underground passage, for when it comes out it is free from all organisms. Evidently it has come through cleansing fires in its subterranean course. The climb of 800 feet up to the plateau above was stiff; but the road was in excellent order, and continued its way up on a steady, if severe, grade.

Once on the top, we were in the country of the Bataks, a people in many ways different from the Malays, and slow to come into contact with the white man. At 1800 feet we passed the house of a missionary, who has long been established among these people, and whose existence was at one time more than a little precarious. From time to time we passed curious-looking objects, resembling gigantic beehives. I made the very bad guess that they were huts, but was told they were stacks of rice straw.

The road was winding about now rather uneasily, for the general gradient of the land had risen to about 5 percent. We soon reached 850 metres (2800 feet). The road now runs in almost a straight line to the Sanatorium, situated at a level of 3000 feet above the sea, and backed by the main mass of the mountains. From this point the road begins a long zigzag up the mountain side, with a sheer rise of 1200 feet in what would probably be only a mile on flat land. As it twists and turns on itself, it strongly reminds one of the climb to Lake Chuzenji in Japan. At 8.30 a.m. we stopped at the top of the hill for breakfast, for which we were all ready. No less did we enjoy the view, which was truly magnificent; for we could see away to Medan, and all the surrounding country, although not the sea beyond Medan, because of a slight haze.

The next portion of the road was no less grand than what we had come over; crossing a watershed, we looked down on the land south of Medan. Suddenly, after a few more turns, we left the Pass, and almost in a twinkling the huge jungle gives place to the wide, open Highlands of Sumatra. The change is extraordinarily sudden. The great jungle trees are, I suppose, the product of hot mist and currents rising up the valleys. At the summit these currents continue upwards, and the vegetation on the plateau gets no benefit from them. Whatever the explanation, the change is very sudden. In one moment we are in the most magnificent tropical jungle; in the next, in open plain covered with grass or small scrub. Far away in front is the great inland lake, Toba-mere, and at least 50 miles away in the same direction we see three extinct, but almost perfect, volcanic cones.

Three or four miles from the Pass are the bungalows belonging to the Deli Maatschappij and other companies, who realise the importance of giving their employees a change to the cool as frequently as possible. The bungalows are substantially built, and command magnificent views of the lake in front, and of Sampoelanangin, the smoking volcano, behind.

Here our party broke up. Drs Kuenen and Vorvoart went off to take samples of water from a proposed supply which was to bring water from the hills to the bungalows by gravitation.



Mr Swellengrebel and I went to the Batak village of Brastagi. The village consisted of a number of houses like Noah’s arks on stilts, in each of which live a number of families in separate cubicles. In the centre of the village was a building, to which I was told all youths were banished from the parental abode when they had reached the age of indiscretion.

Photograph of terraced rice paddies in Brastagi, Sumatra
Figure 6.3: Rice fields at Brastagi, in the Bakak Highlands of Sumatra

In other respects the social conditions were as different to those in the Federated Malay States as could be imagined, and many curious things were seen. Very heavy earrings are worn by the married women. They consist of coils of silver so heavy that they must be supported by a cloth over the head. Were the support to give way, the ear would be torn. Old-fashioned ladies wore these continuously throughout their lives, for the silver was coiled in situ and could not be removed; up-to-date matrons have had a screw-joint put in the middle of the ornament so that it can be removed. I wonder if the old dames can see in this simple consideration for comfort a sign of loss of self-respect and modesty in the rising generation?

In the village we examined twenty children without finding an abnormal spleen. Only one little girl looked ill. On inquiry we found she had suffered from dysentery for a fortnight, so we arranged for her to get medicine at the bungalow, which she did. The village is on the edge of a gorge, into which we descended by an almost vertical path, consisting of steps cut in a little funnel in the side of the cliff. At the bottom a large stream of water gushed from the rock, and was then made to irrigate rice fields in the valley. These were admirably constructed in the usual descending series. Both in the rice fields and in the grassy channels we found Anopheles larvae in abundance, but unfortunately all the large ones died on the journey down, and the species was not determined.

Late in the afternoon, on our way back to Medan, we ran into heavy rain at the Pass. Great clouds of vapour were rising from the valley below, and it was now easy to understand the magnificent jungle even at this height. The rain cleared off while we were actually descending the steepest part of the mountain; but from the Sanatorium to the plateau it lashed as only a tropical storm can lash. The rainfall at the plateau is said to be 6 metres (about 240 inches) per annum. I believe it, after what I saw.


List of the Anopheles of North-east Sumatra

March 10th. The forenoon was spent in the laboratory with Dr Schüffner and Mr Swellengrebel in examining the larvae that I had collected. Unfortunately, almost all the pupae and the largest larvae had been killed by the long motor journeys, and the identification of the small ones was not always possible. However, the points of most importance in the specimens that we had gone over, and the confusion of the nomenclature of species, were cleared up as far as possible.

Many months later I heard from Mr Swellengrebel of the result of further investigation of the Anopheles of North-east Sumatra. He wrote that neither he nor Dr Schüffner could find A. maculatus, although they had “tried hard to find it. In Sibolga (N.W. Sumatra), where malaria tropica is prevalent, Dr De Vogel and myself only found A. sinensis, A. ludlowi, and A. rossii. Probably A. ludlowi is the carrier here.”26 The Anopheles that they did find are listed in Table 6.9.

Table 6.9: Anopheles species in North-east Sumatra, as identified by Dr Schüffner and Mr Swellengrebel
A. rossii A. ludlowi A. albirostris
A. tesselatus A. leucosphyrus A. kochii
A. sinensis A. barbirostris A. albotaeniatus


As I said in the beginning of these notes, it was not to be supposed I could make original observations on malaria in the short time spent in the various countries visited in my journey. My object was the simpler one of hearing from the medical men on the spot, their views on malaria; of seeing to what extent their experience coincided with my own, and where it differed, in trying to account for the difference.

So it may be convenient here if I summarise my impressions—for I can call them nothing more—of the portion of Sumatra that I have visited:

  1. 1.That on the sea coast, as in Malay, malaria exists.
  2. 2.That farther inland, malaria is to be found in swamps on the sides of rivers.
  3. 3.That very rarely malaria may exist in elevations up to 1000 feet; but
  4. 4.That for all practical purposes the hill land corresponding to our hill land in Malaya is non-malarious.
  5. 5.That an admirable system of hospitals exists.
  6. 6.That whether or not indentured labour may be undesirable ultimately, at present it is giving the estates in Sumatra a much better start than they have in the Federated Malay States; and finally,
  7. 7.That with equality in land and climate, and labour extraordinarily free from malaria, Sumatra will ultimately become one of the finest tropical agricultural countries in the world.