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berkeibiTN
LIBRARY

UNIVERSITY OP



CALIFORNIA



RURAL SANITATION IN THE TROPICS



PRINTED BY

OLIVER AND BOYD

EDINBURGH, SCOTLAND



RURAL SANITATION
IN THE TROPICS

BEING NOTES AND OBSERVATIONS IN

THE MALAY ARCHIPELAGO, PANAMA

AND OTHER LANDS



By MALCOLM WATSON

M.D., CM., D.P.H.



WITH ILLUSTRATIONS



LONDON

JOHN MURRAY, ALBEMARLE STREET, W

1915






PUBLIC
HEALTH
LIBRARY



A II rights reserved



TO

SIR RONALD ROSS, K.C.B.

D.P.H. F.R.C.S., M.D., D.Sc, LL.D., F.R.S.

NOBEL LAUREATE

I DEDICATE THIS BOOK

NOT ONLY

AS A TOKEN OF PERSONAL ESTEEM AND FRIENDSHIP

BUT ALSO

AS A TRIBUTE OF PROFOUND ADMIRATION

FOR HIS GENIUS AND HIS WORK



41S410



PREFACE

In the text I take the opportunity of expressing my
thanks to many of my colleagues in the medical pro-
fession, and others who so generously helped me in
the different countries that I visited. Here I wish
to tender respectfully my thanks to His Excellency
Sir Arthur Young, K.C.M.G., Governor of the
Straits Settlements and High Commissioner of the
Federated Malay States, for the credentials with
which he provided me; to His Excellency Sir
Walter Egerton, K.C.M.G., who invited me to
make my headquarters at Government House, and
in other ways assisted me in British Guiana ; and to
Colonel Goethals, Governor of the Isthmian Canal
Zone, and Colonel Gorgas, for their assistance in
connection with my visit to the Panama Canal.
And finally, for revising the proofs of this work and
for seeing it through the press, I am indebted to
George S. Middleton, M.D., LL.D., late Senior
Physician to the Glasgow Royal Infirmary. To find
myself again associated in work with a beloved
Teacher and inspiring " Chief" brings back the breath
and bloom of the happy years spent in the G.R.I.

M. Watson.

August 191 5.



CONTENTS



Introductory



CHAPTER I



PAGK
I



CHAPTER n

BRITISH MALAYA

History. Klang. Choice of Anti-malaria Method. Port
Swettenham. Results. Rural Malaria. Malaria Easily
Controlled in Flat Land. Hill Land. Persistence
of Malaria. Subsoil Drainage and its Problems. The
Area to be Drained. Stone Covering. Spleen Rates and
Death-rates .......



CHAPTER HI

BRITISH MALAYA {continued)

Malaria Advisory Board, Federated Malay States : its Objects.
Malaria in Kuala Lumpur. Quinine. Pictorial Card.
Research. Terentang Estate Experiment. The Anti-
malaria Committee of the Straits Settlements. Malaria
in Singapore. Rice P^ields and Malaria. Water-supplies
in the Federated Malay States. The Coast Water Scheme.
Rules for Estate Sanitation. Beri-Beri



. CHAPTER IV

QUININE PROPHYLAXIS IN ITALY

Distribution of Malaria in Italy. Economic Importance of
the Disease. Its Connection with Swamps. Physical
Conditions Favouring Malaria. Drainage Difficulties.
Quinine. Council of Health . . . . .40



X CONTENTS

CHAPTER V

MALARIA IN INDIA

PAOB

Malayan and Indian Observations, a Parallel. The Human
Factor in Malaria. Jungle in Lower Bengal. Hill Land
in Central Provinces. The Identification of Anopheles
maculatus. The Duars. Jeypore Agency. Chota Nagpur.
Ceylon ........ 47



CHAPTER VI

NOTES ON SUMATRA

Position. Belawan. Medan. Tobacco Cultivation. Tand-
jong Kassau, a Healthy Estate. A. maculaitts absent.
The Hospital. Vital Statistics. Mosquitoes. Toentoen-
gan, a Typical Hill Land Estate yet free from Malaria.
Labour System in Sumatra. Deli Maatschappij. Hospital
at Medan. Vital Statistics of Ten Thousand Coolies.
Ankylostomiasis. Malaria. Dysentery. Principal Diseases.
Medical Institute. Bekioen and Bandar Talu, Hill Land
Estates, Sumatra's Profile. Kuala Namoe Estate, formerly
Malarious. Tandjong Morawa Hospital. Dr Schiiffner.
Rantau Pandjang. Malaria on the Sea Coast. Method of
Obtaining Children for Spleen Examination. The Sumatra
Highlands. The Military Road. A Canyon. Sudden
Change in Vegetation. Brastagi : no Malaria ; many
Anopheles in Rice Fields. List of Anopheles of North-
east Sumatra. Conclusions . . . . -59



CHAPTER VII

HONG KONG AND PHILIPPINE* ISLANDS

Hong Kong. Formosa. Philippine Islands. The Distribution

of Anopheles in South and East Asia . . • 90



CONTENTS xi

CHAPTER VIII

PANAMA

rAGR

History of Failures. Why the Americans began the Canal.
Preparation for the Labour Force. My Failure to Under-
stand the Sanitary Work. Criticism of the .Sanitary
Work. First Impressions. Esprit de Corps. Yellow
Fever and Malaria in the Past. Yellow Fever among the
French. Highest Officials not Exempt. Doctors and
Nurses Attacked. Death-rate of French Labourers. The
Americans begin in 1904. Work temporarily abandoned in
1906. The last Yellow Fever Epidemic. Malaria . . 99

CHAPTER IX

PANAMA {continued)

The Organisation of the Department of Sanitation. Signifi-
cance of the Name. The Three Sub - departments.
Sanitary Inspection and Prevention. Hospitals and Board
of Health Laboratory. The Geography of the Isthmus and
Canal. The Tides of the Atlantic and of the Pacific.
Temperature. Rainfall. Division into Sanitary Districts.
The Area of Districts. The Chief Sanitary Inspector's
Staff. Manual of Instructions for Sanitary Inspectors . 119

CHAPTER X

PANAMA {continued)

Ancon and Balboa. Filling a Swamp. Soft Stone from
Culebra Cut. Range Closet. Subsoil Drains. Hydraulic
Fill. Screened Barracks. Gatun. The Yellow Fever Ant.
An " Hydraulic Fill." Breeding Mosquitoes. Fish and
Larvse. Y.M.C.A. Subsoil Drain Blocked. A Wire
Drain. Native Tenements. Channels in Argillaceous
Sandstone. A Sanitary Inspector's Office. Miraflores.
Grass-burnt Drain. Rock Pools. The Anopheles Catch.
Rio Grande Swamp. East Miraflores Dump. Camatillo
Swamp. Larvacide and Oil used. Gorgona. Condensing
Station. Reservoir Larvae in Debris. A. albimanus not in
Streams. Algae. The Breeding-place of A. malefactor.



xii CONTENTS

PARE

Oiling Swamps. No " Clean - Weeding." The Mosquito
Catch, Matachin. Larvas Found. " No Pupse Allowed."
Culverts Blocked. Swamp Vegetation in Panama. The
Chagres River. Larvs in Debris. "Seaweed" Grass.
Bas Obispo. A "Mosaic" Breeding-place. The Cut.
Large Population on its Banks. How Rainfall alters
Oiling Areas. Las Cascadas. Drainage done with Brains.
Larvae in Cattle Hoof-marks. Empire. " Stegomyia
Day." Prosecutions for Sanitary Offences. The Beginning
of Wisdom. Culebra. " Filling " Blocks Drainage. An
Unsatisfactory Latrine. Lady Complains of Mosquitoes.
My Experience of Mosquitoes. Pedro Miguel. Oil-
Tanks. Oil-Boat. Locks. Rio Pedro Miguel. No
Larvie. Refuse Destructor. " Pick-up Day." Paraiso.
The Cut. Cucaracha Slide. Iced Water, Colon.
Cristobal. Mount Hope. Houses on Piles. Original
Town on a Coral Reef. Drainage. Spleen Rate in 1904.
Toro Point. Houses on Coral Beach. Swamp behind.
Larvic in Stream. Reduction of Malaria. Corozal.
Frijoles. Monte Lirio, The City of Panama . -133



CHAPTER XI

PANAMA {continued)

Anti-malaria Methods. Drainage. Open Drains Dangerous
in Dry Weather. Upkeep Expensive. Subsoil or Tile
Drains. Stone Covering. Blockage. Wire Drains Cheap ;
Suitable only for Certain Countries. First Use of Tile
Drains in Malaya. Oiling, Second to Drainage in
Principle ; First in Practice in Panama. Oiling System.
Labour Saving. Cost of Labour. Sprayers. Drip Barrels.
Larvacide Manufacture ; Value ; Disadvantages. Screen-
ing. The New House. Quality of Gauze. Are Screened
Houses Mosquito Traps ? Screening Abolished for " Silver
Married Quarters" in 1909. Extension of Oiling. Number
who Live in Screened Houses. Quinine . . . 168



CHAPTER Xn

PANAMA {continued)

On Mosquitoes. Aedes {Stegomyia) calopiis and Yellow Fever.
Lives in Rain-water, not in Pool. Asia's Danger. Tokyo.
West Africa. Anopheles and Malaria. Species on Zone.



CONTENTS xiii

PAGE

Atiophclcs albi/nanus. Dr Darling's Observations Outside
the Zone. A. ar^yritarsis. A. psetidopnnctipentds. A.
malefactor. A. eiseni. A. crtizi. On Anopheles Adults.
Distance of Flight. Flights at Gatun. Miraflores and
Corozal, The Effect of Wind on, and the Diffusion of,
Mosquitoes. Mosquito Traps .... 184



CHAPTER XIII

PANAMA {continued)

Weekly and Monthly Inspection Reports by Sanitary Inspectors
and District Physicians. Water-supplies. Sewage System.
The Commissary and Subsistence Department . ,211

CHAPTER XIV

PANAMA {continned)

The Board ol Health Laboratory. Multifarious Duties. Re-
search. " Studies in Relation to Malaria." Treatment of
the Sick. The Hospitals. Sick Camps. Blackwater
Fever. The Canal Zone Medical Association . . 225



CHAPTER XV

PANAMA {contimied)

Results from Sanitation. General Death-rate. Individual
Diseases. Does Sanitation Pay ? The Labour Problem
in 1906. Solution in igo8. The Racial Distribution of
Employees of the Canal Commission, and their Manner of
Living. Racial Death-rate. Blackwater Fever in West
Indians. Pneumonia ; Why it Disappeared. Yellow
Fever Extinguished ; Statistics of the Last Epidemic,
1904-5. Malaria Controlled. Admission Rate. Special
Difficulties on the Zone. Malaria in Small Stations and
Camps. Juan Grande Camp. Mamei Camp. Porto
Bello. Empire. Mosquito Catching and Screening. A
Sanitary Trial Balance. Deportations. Immigrants Ex-
cluded. The True Number of Employees. A Modern
Miracle . . . . . -235



xiv CONTENTS

CHAPTER XVI

PANAMA iconthijied)

PAGB

Cost of Sanitation. The Total Expenditure. What the Depart-
ment of Sanitation is. The Department of Municipal
Engineering. Scavenging. Buildings and Quarantine.
Administrations. Hospitals. Sanitation Proper. Cost per
Head. Cost per Acre. Special Conditions affecting the
Cost. The Lesson from Panama .... 260

CHAPTER XVII

BRITISH GUIANA

Introductory. Object of my Visit. Physical Geography.
Vital Statistics of Indian Labour. Georgetown. Sea
Defences. Borrow-pits. Mosquitoes in Georgetown.
Rain-water as a Drinking Supply. Constitution of the
Colony. The Hills Estate. Estates on Coast Line. Irri-
gation and Drainage Systems of Sugar Estates. " Kokers."
Plantation Uitvlugt. Spleen Rate. Hospital. Planta-
tions — Diamond, Providence, Farm. The Courantyne.
Reverend Mr Aitken's Observations. Plantation Port
Mourant. Rosehall School. Plantation Albion. Rice
Fields in British Guiana. Dr Kennard's Observations.
The Future . . . . . . .271

CHAPTER XVni

BARBADOS

Singularity. Reasons for Absence of Malaria. Suggested

Experiment. Conclusion ..... 299

EPILOGUE

The Place of Sanitation in Tropical Colonisation . 308



LIST OF ILLUSTRATIONS



FIO.
I.

2.

3-

4-

5-
6.

7.
8.

9-

lO.

II.

12,

13-

14.

15-
16.

17.
18.
19.
20.
21.
22.

23-
24.

25-

26.

27.
28.
29.



Map of South and East Asia ....
Chart showing Variation of Death-rate with Spleen Rate

Bukit Ijok Estate, Federated Malay States. Subsoil
Drainage .....

Sketch Map to show Variation of Endemicity in Bengal
and in District of Klang, Federated Malay States

Sumatra. Toentoengan Estate

Sumatra. Toentoengan Estate

Sumatra. Toentoengan Estate

Sumatra. Bandar Talu Estate

Sumatra. Rice Fields in the Barak Highlands

Hong Kong. Natural Nullah or Mountain Stream

Map of the Isthmus of Panama

Panama. Ancon Hill and Swamp

Panama. Subsoil Drain

Panama. " Hydraulic Fill" at Balboa

Panama. Sketch Map of Gatun

Panama. Dead Jungle at Gatun

Panama. " Hydraulic Fill " Finished

Panama. Unscreened Houses

Panama. Drained Ravine at Gatun .

Panama. Undrained Ravine at Gatun

Panama. Burnt Drain at Miraflores .

Panama. On the Waggon Road at Miraflores

Panama. A Knapsack Sprayer

Panama. Sprayers at Work .

Panama. Driftwood on the Chagres River .

Panama. The Rio Mandingo at Bas Obispo

Panama. The Cut at Bas Obispo

Panama. An Oil Cart

Panama. " Filling " at Culebra

XV



PAGE

5
12

16



66
66
66
76
76
90
122
132
134
134
137
138
140
142
144
144
146
146
14S
148
152
154
154
154
156



XVI



ILLUSTRATIONS



30-
31-
32.
33-
34-
35-
36.
37.
38.
39.
40.
41.
42.

43.
44.

45-

46.

47-



49-
50.

51-
52.

53-
54.

55-
56.



Panama. A Stream Blocked by " Filling "

Panama. Pedro Miguel

Panama. Lake at Pedro Miguel

Panama. The Culebra Cut

Panama. Colon Hospital

Panama. On the Road from Colon to Mount Hope

Panama. A Swamp at Mount Hope .

Panama. A Drain at Gatun .

Federated Malay States. A Drain in Kuala Lumpur

Panama. Mule Carrying Oil .

Panama. Screened Houses at Corozal

Panama. Screened Ward, Ancon Hospital

Panama. .Screened Railway Waggons

Panama. Screened House, Ancon Hospital

Panama. Sanitary Inspector's House, Frijoles

Panama. Chart of the Malaria Rate and Mosquito Catch

at Corozal ....
Panama. A Mosquito Trap .
Panama. The Reservoir at Gorgona
Panama. Chart of Malaria in Canal Zone from 1906

to 1913 .....

British Guiana. The Sea Defences .
British Guiana. A " Koker " .
British Guiana. An Estate Hospital .
British Guiana. A Trench at New Amsterdam
British Guiana. On the Road to Port Mourant
British Guiana. Navigation Canal and Coolie Lines at

Plantation Port Mourant
British Guiana. Coolie Yard at Plantation Albion
British Guiana. Trenches at Plantation Albion



RURAL SANITATION IN THE
TROPICS

CHAPTER I

INTRODUCTORY

To one who, like the author, has the direct responsi-
bility for the health, and so for the efficiency, of a
large force of tropical labourers, the unavoidable
isolation from fellow- workers is a source of constant
anxiety. Ever before him there is the fear that his
views may become narrow and fixed from constantly
seeing- the same surroundings, and that his ideas
would be altered had he more knowledge of what was
happening in other places. The waste of only a
single cent a coolie a day on a labour force of forty
thousand means a direct loss of 126,000 Straits
dollars (almost ^15,000 sterling) per annum; and
to increase the efficiency of the labour by a cent
a day means a corresponding gain. Books and
papers are valuable ; but of more value still is a
meeting with their authors, and an actual view of
the field in which they work. Such thoughts and
such fears have driven the writer to spend time and
money in visiting other lands, so that he might
benefit those under his care. In this book I have
recorded what I saw and what I thought.

It includes a detailed account of the Sanitary
Organisation in Panama, the Mecca of the modern
Sanitarian, There he learns how one of the largest
labour forces that the world has seen has been built

A



'2 INTRODUCTORY

up, and kept at a higfh degree of efficiency, In one
of the deadliest climates in the tropics, when engaged
on a great engineering- work. My visit to British
Guiana was made to determine the health conditions
of another larg^e labour force, also in the American
tropics, when engaged in agricultural pursuits. But
as a man, however careful he may be, can hardly
help seeing- throug-h his own spectacles, I have begun
with a chapter on sanitary work in the Malay States,
and have there recorded some of the conclusions
to which I have been led, and which seem to me
to throw light on malaria in Italy, India, other
parts of Asia, and the g"reat Eastern Archipelago.
My visit to Sumatra showed what excellent work
is being done there to improve the health of large
labour forces eng-aged in tropical agriculture.

Everywhere throug-hout the tropics great sanitary
activity, and scientific investigation of disease, have
followed Ross's epoch-making discovery of the role
played by the mosquito in the propagation of malaria.
From India, from the Philippines, and from other
countries, a series of invaluable reports are being
issued, which will before long go far to make the
tropics, if not a permanent home for the white races,
at least a part of the world in which the white man
may live with little more danger to health than
in his own country. From the early chapters the
reader will be able to gauge the views, and perhaps
the bias and prejudices, of the author, when he set
forth on his travels.



CHAPTER II

BRITISH MALAYA

History. Klang. Choice of Anti-malaria Method. Port Swetten-
ham. Results. Rural Malaria. Malaria Easily Controlled in
Flat Land. Hill Land. Persistence of Malaria. Subsoil
Drainage and its Problems. The Area to be Drained. Stone
Covering. Spleen Rates and Death-rates.

History. — Surveying- the recent history of Egypt,
Lord Cromer writes: "It may be doubted whether
in any other country such a remarkable transforma-
tion has been made in so short a time." Had he,
however, turned his eyes eastward to the Malay
Peninsula, he would have found a transformation
no less remarkable, and due, moreover, to adminis-
trators of no other than his own race. But if the
happy results from brilliant administration are the
same, the parallel ends there. In Egypt the adminis-
trator revived a country whose civilisation is the |
oldest in the world, and rescued a people whose ^
history forms the earliest records of the human race :
in Malaya a new country, appeared new-born from /
the womb of Time, where it had slept since the world »
began. In Egypt engineers brought water from a
river to a sandy waste, and turned a barren desert
into fruitful fields : in Malaya a jungle, watered by
the copious rains of heaven, covered the country as
an evergreen robe ; and if, for a time, man's efforts
have driven it back, silently and stealthily it ever seeks
to resume its sway. In Egypt an industrious people
were the victims of virile alien hordes : in Malaya a
scanty thriftless native race preyed on the few who



4 BRITISH MALAYA

came to work. Egypt was made great through the
industry of her own people in her fields : Malaya
has become fruitful by the peaceful immigration of
strangers who work mainly in her mines. But in
both countries firm and honest rule has brought an
era of peace and plenty, of which our race may
indeed feel proud.

Forty years ago the Malaya Peninsula slept in
her jungle, hardly disturbed by a few Chinese miners,
who scratched the surface of the soil in search of tin.
Her own people, the Malays, lived on the rivers, for
there were no roads ; grew a few grains of rice, and a
few bunches of fruit ; possessed no property, for that
only made life more insecure ; and robbed the Chinese
miner or any other passer-by, if he seemed too weak
to resist attack. From time to time, perhaps for the
sake of variety, they molested the traders of the
neighbouring British colony.

At last a peculiarly brutal piracy committed on
a British ship, and the impossibility of tolerating
almost continuous strife just without, and sometimes
within, her borders, drove the governor of the colony
to assume a certain control over the native rulers.
By degrees, and to the great advantage of the whole
land, the administration passed into the hands of the
British. Peace being established, the Malay now
felt secure, and in a land so fruitful soon accumulated
what to him was untold wealth. Sure of the fruits of
their labour, the Chinese poured into the country,
and worked with such vigour that the Federated
Malay States have for a generation past produced
almost two-thirds of the world's tin. Wisely expend-
ing the revenue from tin on roads and railways to
open up the country, the administrators attracted
planters from Ceylon, who grew coffee, rubber, and
cocoa-nuts, and turned useless jungle into wealth both
for themselves and the country ; until in the space of
one generation the country became one of the most
prosperous on the globe.



HISTORICAl. OUTLINE 5

Towns with well-built houses, broad streets, and
pure water-supplies have sprung into existence where
only a few years ago the tiger hunted his prey-




Fig. I.— Map of South and East Asia.



There are schools for the children, hospitals for the
sick, and pt«:e-4ustice for the litigant and lawless ;
while posts, telegraphs, roads and railways, second



6 BRITISH MALAYA

to none in cheapness, link up the whole land. And
all this prosperity has been built up with labour
which has been "free" in the truest and broadest
sense of the word. A slave there has never been.
At first there was a small percentage of labour
indentured to remain on the mine or estate for a
period not exceeding" three years ; but even indenture
is now abolished. No coolie can be charged even
with the cost of bringing him to the country ; while
he may walk off at any time on giving a month's
notice, or paying a month's wages. The proof of
the success of the system has been the large number
of poverty-stricken coolies who came from India
and China ; the large sums remitted back ; and the
prosperity of the whole country.

But from time to time the immigrants found them-
selves checked by those diseases, often so mysterious
in their origin, which have haunted and harried all
attempts at tropical colonisation. Of my experience
of malaria, the greatest, or shall I say the worst, of
these diseases, I now propose to write ; adding later
on some remarks on beri-beri and other sanitary
problems.

Klang. — On assuming duty as District Surgeon
of Klang, Federated Malay States, early in January
1 90 1, I found that a very large percentage of the
patients in my hospital suffered from malaria. Not
only was the town of Klang full of malaria, but the
whole coast-line was suffering from a "wave" of the
disease. The little town of Jugra, twenty miles south
of Klang was so unhealthy that a proposal to remove
it bodily was being discussed. As a student of the
London School of Tropical Medicine, I was familiar
with the malaria parasite, and I was also aware
of Ross's discovery that Anopheles carried malaria.
It appeared to me that ward after ward might be
built to accommodate the increasing number of
patients without any very substantial advantage to
the community ; for only a small fraction of the sick



MALARIA AT KLANG 7

would ever come to hospital ; or, if they came, could
be accommodated in the hospital, however much it
was likely to be extended. It was clear to me, that,
even at the risk of being accused of neglecting my
patients and "wasting my time on research," it was
my duty to spend some of my time in studying the
disease outside of the wards, and to make some
attempt to prevent people from getting the disease.

It was necessary first of all to obtain an accurate
knowledge of where the malaria cases came from,
and statistics were carefully prepared. The breeding-
places of Anopheles were next sought out, and marked
out on a plan. Then came the really difficult question,
what method was to be adopted to stamp out the
disease. Medical opinion was strongly divided then,
as it was to be for many years after. Fortunately I
made what was to prove in the end, the right choice.
The position will be realised from the following
paragraphs extracted from an earlier work of my



" At this time, Ross's brilliant discovery had been fully
confirmed by the Italians and others. Manson's dramatic
proof at Ostia and at London left no doubt of what could
be done under certain conditions. Ross himself had
favoured mosquito reduction, and was actively engaged in
West Africa in putting this method to the test. The
Italians were rather in favour of mechanical prophylaxis
by mosquito netting, and by the use of quinine, and Koch
had already reported a success in a small community by
the regular use of this drug.

" At this time nothing was known about the species of
Anophelines, and the valuable reports of the Commis-
sioners of the Malaria Committee of the Royal Society
bearing on the importance of species were not published
until the year after the works at Klang had been begun.

" Clio ice of Anti-malaria Method. — At Klang the work
of eradicating malaria seemed wellnigh hopeless. No
hot or cold season even temporarily stopped the mosquito
pest, and every well, ditch, and swamp teemed with larvae.

• The Prevention of Malaria in the Federated Malay States, by
M. Watson, p. 14.



8 BRITISH MALAYA

The active co-operation of the native community could
not be expected, and active resistance, especially from the
Chinese, was certain if any attempt were made to enforce
the use of quinine. The enforcement of mosquito nets
was, of course, impossible, since this would have meant
constant house visitation at night. Compulsory screening
of the whole of all the houses was impossible, for financial
reasons. The large acreage of swamp, the heavy rainfall,
and the amount of supervision required, apart altogether
from its cost and temporary efficacy, prohibited the use
of petroleum,

" Again, with an area so extensive, subsoil water so



Online LibrarySir Malcolm WatsonRural sanitation in the tropics : being notes and observations in the Malay Archipelago, Panama and other lands → online text (page 1 of 26)