in trying to persuade the world that he had discovered the " Anopheles malariferi
indipendentemente da Ross" [1900, p. 31]. Unfortunately for him he had referred
to my work in a paper [October 1898] which he had published two months before
he "discovered" anything at all. There is no doubt that he and his colleagues
recognised the genus of my "dapple-winged" mosquitos from several statements of
mine, and were thus able easily to find the parasites in members of the same group in
Italy. The Italian work was due mainly to Bignami and Bastianelli, and not to this
author as erroneously stated in many monographs and articles. Laveran has made
similar remarks about his own work [1907, p. 13J ; and the matter is mentioned here
because such misstatements are apt to discourage genuine work [Ross, 1905].



28 HISTORY ., ^[Sect.

In November 1899, I^- Koch, who has given suclT great
discoveries to pathology, added another in connection with
malaria. He found in the valley of Ambawara in Java that
while large numbers of the native children showed the parasites
in their blood, the adults seemed to be comparatively free from
them, and had obviously become partially immune. Thus in
most very malarious places it is chiefly the children who
suffer from the acute disease. The blood of those who survive
gradually produces something which after a number of years
has the power of reducing and perhaps extinguishing the
parasite invasion. From this it follows that in such localities
the Anophelines must become infected principally from the
native children {see section 31 (9)).

In the summer of 1900, P. Manson carried out an important
crucial experiment. A number of Anopheles maculipennis, fed
on cases of mild tertian, were brought from Italy to London,
and were allowed to bite P. T. Manson there on several
occasions. He developed the disease on the 13th September,
the tertian parasites being found in his blood a little later.
The insects were also allowed to bite G. Warren, who was
similarly attacked fourteen days afterwards. At the same
time L. Sambon, G. C. Low and two others lived for three
of the most malarious months in one of the deadliest places
in the Roman Campagna, Ostia, without contracting the
disease, because they spent the nights in a hut protected by
wire gauze against the entry of mosquitos.

On many other occasions healthy persons have been
similarly infected on the lines of my experiments with birds
in July to August 1898. As already mentioned Bignami and
Bastianelli infected four persons in Rome (which is itself free
from malaria) in 1898- 1899. Subsequently C. F. Fearnside at
Rajamundri in India infected seven out of eight persons,
including himself, in 1900-1901 [1901]. W. Schiiffner infected
himself and two others at Delhi, Sumatra, in August and
September 1901, two with tertian and one with malignant



7] PREVENTION 29

malaria, by means of certain Anophelines [1902]. N. Jancso
infected ten out of fifteen persons at Kolozsvar in Hungary
in 1904 by means of A. maculipennis (section 17).

My work on the Proteosoma of birds has been confirmed
by Koch [1899], C. Daniels [1899], B. Grassi [1900], R. Ruge
[1901], Ed. and Et. Sergent [1907], R. O. Neumann [1908].

The mosquito cycle of the human parasites has been further
worked upon by Fernside [1901], Stephens and Christophers
[1899-1903], Schiiffner [1902], Jancso [1904], Schaudinn and
others.

Reviewing this history we shall see that the great stream
of research on malaria, descending to us through more than
two thousand years, is composed of three main tributaries
finally mingled together. One tributary rises in the work of
the ancients on the different clinical forms, and consists of
the discovery of the cinchona bark ; the work of Torti (1753) ;
the discovery of the plasmodin by Meckel (1847); of the
parasites by Laveran (1880); and of the confirmations and
extensions of Golgi, Danilewsky and many others.

Another tributary consists of the ancient observations con-
necting the disease with marshes ; the speculations of Varro,
Columella, Lancisi, Beauperthuy, King, Laveran, Koch and
Manson ; and the valuable researches of those who tried to
find the organism in marshes.

The third tributary consists of the early work on para-
sites ; the discovery of metaxeny by Abildgaard (1790),
Steenstrup (1842), and Kiichenmeister (1851); the discoveries
of Leukart, Fedschenko (1858), Melnikoff (1868), Manson
(1877), regarding certain worms; that of Smith and Kilborne
(1889) regarding Piroplasma ; of Bruce on trypanosomes my
work on human and avian malaria (1895 -1899); and the
confirmations and extensions which followed.

7. Recent History of Prevention. — It is open to question
whether the extensive drainage works of the ancients had



30 HISTORY [Sfxt.

been carried out for sanitary or for agricultural purposes ;
but there is no doubt that for several centuries the Italians,
and other nations, have known how to control malaria by
drainage and allied measures. In fact, for a long time the state-
ment that drainage reduces malaria has been generally accepted
as a medical dogma. As soon as the mosquito theorem began
to become consolidated, the question arose whether the new
knowledge would not provide us with some easier and cheaper
method of prevention. My own studies had been undertaken
principally for this object ; and the following observations
of mine were connected with it.

As early as 1884-1885 in Bangalore, and many times since
then, I had noticed that Stegomyia and Culex could be largely
reduced in numbers in my own house by emptying out the
stale rain-water collected in tubs and pots in the garden.
On one occasion I offered to reduce these mosquitos in the
regimental mess - house, but the adjutant objected because,
he said, I should be disturbing the order of nature ! But I
satisfied myself as to the possibility of making such a reduction
by my own personal experiences in many parts of India.

After incriminating my dapple - winged mosquitos (Ano-
phelines) in Secunderabad in 1897 I studied .their habits
there and in Kherwara, Calcutta, the Darjeeling Himalaya
region, and Assam,^ and noted the following points.
» The eggs of the Anophelines were more or less boat-shaped,
and possessed a peculiar membrane which gave them the
appearance of having a row of oars on either side — thus
differing from the eggs of the Culex and Stegomyia. They
were also apt to arrange themselves in triangular patterns on
the surface of the water. The larvae floated flat on the surface
and had no long breathing tube — being thus unlike those of the
other common groups. The adults were generally differentiated
by having spotted (dappled) wings ; a shape more suited for

1 I could obtain no information on mosquitos in India at that time, not even at
the Indian Museum in Calcutta.



7] PREVENTION 31

long flight ; and a peculiar attitude, when resting, at an angle
to the surface to which they clung. These points would enable
any one, even uneducated labourers, to distinguish them. But
above all, my native assistants and myself noticed everywhere
that the larvae do not generally breed in the pots and tubs
occupied by those of the other groups, but mostly in pools of
water on the ground. This led me at once (1897) to the
explanation of the central fact that malaria is connected with
marshes. If Culex and Stegomyia had been responsible for the
disease it would not have possessed this relation — it would have
been connected with pots and tubs, etc., just as yellow fever,
which is carried by Stegomyia, is connected with them. 1 did not
then know that the quartan and tertian parasites are also carried
by Anophelines, but guessed, from the well - known relation
referred to, that they were carried by some kind of marsh-breed-
ing gnats, and not by the pot-breeding ones. The explanation
was now clear ; the ancients were quite right — the disease is
caused by an emanation from the marsh. That emanation, how-
ever, is not a gas, nor even a contagimn vivum, but an insect.

It was observed also that the Anophelines do not breed
so much in large open bodies of water, such as lakes, rivers
and reservoirs, but more in small, shallow, and often grassy
pools and puddles where they can obtain shelter from wind
and fish ; and that like other mosquitos, they abound most in
proximity to their breeding - places. Putting all these facts
together, I reasoned that we now possessed a much cheaper
and easier method of prevention. Previously, we had been
obliged to drain a whole area at great cost â–  now we should
be able actually to seek out and determine the exact malaria-
producing pools, namely, those which contain the larvae, and
then to fill up or drain these alone ; and I naturally inferred
that if the old method had been feasible (as it had been in
many places), the new method would be still more easily
feasible, and at less expense.

Before leaving India I described my proposals in a short report



32 HISTORY [Sect.

to Government, dated the i6th February 1899, and published
five months later without date, and with a title given apparently
by the editor [1899]. The matter is so important, and my
views have been so much misreported, that I must reiterate
exactly what I said. I pointed out that mosquitos in general
" are seldom to be found in the larger bodies of water " ; that
to get rid of them locally " it will suffice to empty out or drain
away or treat with certain chemicals the small collections of
water " in which they breed ; that the Anophelines " seem to
choose only rain-water puddles and ponds too large to dry
up under a week or more, and too small or too foul and stagnant
for minnows." I said that such pools "are not common in
most parts of India except during the rains," and "seem to be
so isolated and small that I think it may be possible to
exterminate this species under certain circumstances." I added,
however, that " I wish to be understood as writing with all
due caution on these points." " I limit this statement to certain
localities only, because it is obvious that where the breeding-
pools are very numerous, as in water-logged country, or where
the inhabitants are not sufficiently advanced to take the neces-
sary precautions, we can scarcely expect the recent observations
to be of much use — at least for some years to come. And this
limitation must, I fear, exclude most of the rural areas in India.
Where, however, the breeding - pools are not very numerous,
and where there is anything approaching a competent sanitary
establishment, we may, I think, hope to reap the benefit. . . .
And this should apply to the most crowded areas, such as those
of cities, towns and cantonments, and also to tea, coffee and
indigo estates, and perhaps to military camps." " In making
these suggestions I do not wish to excite hopes which may
ultimately prove to have been unfounded." I concluded by
urging further investigations on the malaria-bearing mosquitos
of India and their habits. Though the report, being hurriedly
written, might have been more exactly expressed in places, it
is correct enough.



7] MOSQUITO REDUCTION 33

As it was the original statement of the radical anti-malaria

measure — which has since been used with success in many parts

of the world, and will certainly be adopted in the future as a

fundamental principle of tropical urban sanitation — the reader

should now clearly grasp what exactly was proposed. Animals

tend to abound most where the local conditions are most

favourable to them. Conversely, if we can make the local

conditions unfavourable, they should become less numerous.

Also, malaria being carried by certain Anophelines, should, as

a broad general principle, be most common where they are

most common, and should be reduced where they are reduced.

I proposed, therefore, to reduce their numbers by measures I

directed against their breeding-places. But this proposal was

obviously not meant to apply to the whole world, but only to

places where the measures were most likely to be feasible — that

is, generally to " crowded areas," and not to " rural areas." A

square mile of town, containing thousands of ratepayers, may

be assumed to have money available for such work ; while open

country, containing perhaps only a few scattered houses, has

no such funds. Moreover, mosquito-reduction in a town will

benefit thousands of people, while in the country it will benefit

only a few — and that for the same cost. An identical principle

applies to pipe water-supply and to pipe-sewerage systems —

these are frequently given to towns, but not so often, even

in Europe, to widely-scattered farmhouses. If then, I argued

in effect, a town can afford to provide its inhabitants with a

piped water-supply, or a sewerage system, it ought also to be

able to keep them free, partially at least, from such dangerous

insects as mosquitos. At that time I had had a rather

exceptional experience of practical sanitation, having been

specially appointed by the Government of India to improve

the sanitation of a large Indian town (Bangalore), and I knew

what I was writing about. As a general rule it would be much

cheaper, I thought — and probably every practical engineer or

health officer will agree with me — to make a great reduction



34 HISTORY [Sect.

of mosquitos in most towns, than to instal and maintain a
piped water-supply or sewerage system. I held also — and still
hold — that the same measures might be feasible in some cases,
even in plantations, military camps and villages.^

Unfortunately there are many people who seem to regard
any new idea as a personal affront — who never try to under-
stand the author, who disregard his reservations, and who
attribute to him any absurd opinion ! I was immediately
accused of proposing to destroy every mosquito throughout
India and Africa, and of trying to upset the order of nature,
and so on. Still worse, many others accepted this idea without
understanding the practical details, and did much harm by
attempting the work in quite unsuitable places. Lastly, some
rejected the idea, but pretended to test it experimentally — and
of course failed.

In 1899, owing to the efforts of a number of medical
men and men of affairs, and largely to the recent work
on malaria, schools of tropical medicine were opened in
Liverpool and London. At my inaugural lecture at the former
(published at the same time as the previous paper) I repeated
the same suggestions [1899]. Judging from my Indian experi-
ences, I overrated somewhat the difficulty of reducing Culicines ;
but concluded by invoking experiments on such points.

West Africa, a great country hitherto paralysed by malaria,
had long attracted me as an objective for practical preventive
work, and I dreamed that it might be revolutionised by it.
Hence, no sooner was the Liverpool School of Tropical
Medicine opened, than I proposed to the Committee that I
should be sent there to study the subject in detail. Conse-
quently I left England in July (1899) with Dr H, E. Annett
of the School, and Mr E. E. Austen of the entomological
department of the British Museum, to see what could be done
in Freetown, the capital of Sierra Leone — long known as the

1 Malcolm Watson (section 57) is now extending Anopheline reduction to rural
areas as well as towns. See also sections 42 and 43.



7] MOSQUITO REDUCTION 35

"white man's grave." As already stated (section 5) we quickly
incriminated two local Anophelines, P. costalis and Myzomyia
funesta, as carriers of malaria ; and then set out to study their
habits with a view to elaborating the principle of mosquito-
reduction for practical sanitation.

Before we left it was arranged that our work should be
published anonymously in the medical press as promptly as
possible for the guidance of others ; and I consequently wrote
a series of four articles which were published in the British
Medical Journal in September and October [1899.] The first
two of them described the finding of the carriers ; but the two
latter (30th September, p. 869, and 14th October, p. 1033)
gave the leading points in the habits of the Anophelines, the
broad distinctions between them and the Culicines, the nature
and distribution of their breeding pools, and other matters
connected with the general theory of malaria, together with
a plate showing the characteristic attitude, and one showing
a characteristic breeding - pool. In all these points these
Anophelines of Sierra Leone proved to be generally similar
to those which I had studied in India. The articles drew wide
attention to the subject ; and in fact formed the basis of work
on the reduction of mosquitos for malaria done since then ;
though, being anonymous, they are not often referred to in
the literature of the subject.^

Being obliged to hurry back, we could spend only seven
weeks in the Colony ; and, as we were only private individuals,
we could not carry out our recommendations. In February
1900 we published our report ; in the main body of which I
summed up my results and recommendations with plates and
figures. Operations for reducing the Anophelines were divided
into those meant to prevent their breeding, such as draining

^ In 1899, G. H. F. Nuttall resuscitated some older works about mosquito-reduction.
C. Finlay and A. F. A. King had recommended it hypothetically, and C. B. Aaron,
L. O. Howard and others did practical experiments with oil, and other agencies ; but
these attempts (of which I was ignorant) do not constitute anything like the practical
sanitary policy drawn up by me.



36 HISTORY [Sect-

or filling the pools or treating them with Culicicides (oil, tar,
lime, etc.) ; and the destruction of the adults or larvae. I
devoted a whole section to discussing the local conditions
under which such operations were likely to be successful, and
concluded as follows : —

"(i) Operations against Anopheles are least likely to be
effectual in level, water-logged localities, and in places where
the insects breed in pools which cannot easily be found, or
cannot easily be treated. (2) Operations will probably be
easier in country which is not quite level, or where the rain-
fall is not great. (3) They promise to be very easy in extremely
dry places. Lastly, it goes without saying that we can scarcely
ever attempt to deal with Anopheles in large rural areas. On
the other hand, we may reasonably hope to reduce them, if
not to exterminate them, in the principal centres of population
and civilisation — that is, just in the places where the prevention
of malaria would be most useful — provided always that we
make intelligent and persistent efforts to do so." Also, both
in this report and in a previous small book of instructions
for laymen [1899], I dxscwssed personal prophylaxis by the use
of mosquito nets, etc., and the reduction of Culicines round
houses ; and I also pointed out how much Europeans in Africa
suffered from not being segregated from the natives as they
are in India [February 1900, p. 45].^

I have described these thoughts and studies at some length,
because they constitute the conclusion of my work commenced
five years previously, long before others had considered the
matter worth touching, and therefore have, I think, the right of
priority. But, as I have already stated, immediately after the
publications of my work in the middle of 1898, numbers of
medical men and naturalists began to take up the matter in
many parts of the world. The classification and habits of the

1 I said also on the same page that a single intelligent native agent might "do a
great deal of good " as regards the reduction of Culicines in many towns. On the
strength of this I have recently been accused of proposing to rid the whole of
Freetown of malaria by the services of one man only !



7] QUININE 37

Anophelines and other mosquitos specially interested them,
and innumerable papers and works on the subject began to
be poured out. The entomological results were invaluable.
Whereas in 1898 only about a hundred species of Culicidae
were known, we have now recognised about six hundred, which
have been carefully described in valuable works by E. E. Austen,
G. M. Giles, L. O. Howard, R. Blanchard, and especially in an
exhaustive monograph, by F. V. Theobald, and by many others.
Regarding the habits of the insects my findings have been
generally confirmed, without very much really new matter being
added. Some of the observers, being new to the subject, have
laboriously recorded facts (such as the abundance of gnats near
their breeding-places, or in ground-floors of houses, or in dark
corners, or on dark surfaces, or their transportation by carriages,
and so on) which, I think, were perfectly familiar to all who
have lived much amongst them.^

Returning to the subject of prevention, we must now note
that an important new method was suggested by R. Koch
during his visit to Italy in 1898 — namely, prevention by treat-
ment of cases. This was tried at once by B. Gosio in Grosseto
in Italy [1900]. Towards the autumn of 1899 Koch went with
R. Pfeififer and H. Kossel to Batavia, where he discovered his law
regarding the frequency of infection in native children ; and in
December proceeded to German New Guinea, where he success-
fully used his method of prevention at Stephansort [1900]. This
method is entirely different to the ancient one of drainage, or
to my modification of it. It aims, not at the reduction of the
carriers of the parasites in a locality, but at the reduction of the
parasites themselves by the general and complete treatment by

^ Also many habits have been ascribed to mosquitos, which exist only in the
imagination of the writers. Thus Nuttall says [1899] that Aaron suggested destroying
mosquitos by placing small lamps in trays of petroleum over ponds or marshes round
dwellings. The gnats, attracted by the light, would fall into the oil. In 1900 two
Italian writers, one of whom is supposed to have led the way regarding the mosquito
malaria theory, not only approved this absurdity, but added the suggestion that the
lamps " be furnished with powerful (j-?V) reflectors turned away from the house." I
have never in my life seen mosquitos attracted by lamps.



38 HISTORY [Sect.

quinine of all infected persons in the locality. If this is done,
he argued, the Anophelines, however numerous they may be,
will be innocuous, as they will find no parasites to carry. He
describes the method ably, and says : " After all these experiences
I consider myself warranted in stating that we are in a position,
by means of the procedure which I have described, to make
every malarious region, according to circumstances, wholly or
nearly free from malaria." The method is invaluable, and there
is no real rivalry between it and my method.

Most admirable, too, has been the work in Italy, led by
A. Celli, himself one of the most distinguished students of
malaria. In 1899 he published an excellent text-book, in
which he presented the whole subject of prevention according
to the " new researches," with a history and accounts of various
preventive measures. This was followed by innumerable
researches and practical campaigns throughout the country
— which have made a great reduction in the disease. All
methods have been adopted, but principally perhaps the
various quinine methods. Italy, however, is a temperate
European country, with conditions very different to those
which prevail in the tropics — and the malaria there is mostly
rural.

Still another method consists in the screening of houses
by wire-gauze, a defence long employed in America against
mosquitos. It was now used in Italy against Anophelines ;
was much encouraged by the experiment of L. Sambon and
G. C. Low in the Campagna in 1900 ; and has been widely
employed at Panama.

In 1898, the Colonial Office and the Royal Society appointed
a commission, consisting of C. W. Daniels, J. W. W. Stephens
and S. R. Christophers, to follow up my work. Daniels left
the commission in 1899 after some good work in British
Central Africa ; but the other observers were sent at my
recommendation to West Africa during the same year.
There they continued our researches of 1899, but laid special



7] YELLOW FEVER 39

stress on segregation for Europeans. They found many
interesting facts about mosquitos, and also developed very
fully the subject of infection of native children, and the
causes of local malaria in West Africa. In 1901 they were
sent to India at my suggestion, and continued similar work