R E S E A R C H E S O N M A L A R I A
47
duction) and possibly also from other mosquitoes, and then communicate the
parasites to healthy persons - perhaps by inoculation. It will be seen which
view is right; but in consequence of my negative experiments, the inoculation
theory was not much favoured by me until I made my researches in the Sigur
Ghat (section 12).
My duties at Bangalore continued for a year and a half At first placed upon
special duty to report on the sanitation of the town (80,000 inhabitants), I was
afterwards appointed officiating Residency Surgeon there and was required
to reorganize the whole of the sanitary arrangements, to create a health de-
partment, to participate in a committee designated to reconstruct the munici-
pal regulations, and to contend against several outbreaks of cholera. Conse-
quently I did not possess as much time as at Secunderabad for my researches
on malaria, but nevertheless in addition to the experiments last referred to,
I was able to dissect many hundreds of mosquitoes in pursuance of my princi-
pal plan of campaign. Several agents were employed to collect the larvae of as
many kinds of mosquitoes as possible, especially from several spots whence
most of the cases of fever came; and these insects, belonging to many species
of the brindled and grey groups of mosquitoes,* were all tested by direct
feeding on cases of malaria, especially aestivo-autunmal. But though each
insect was examined with the utmost care, almost every cell being scrupulous-
ly searched for parasites, the results still remained entirely negative.
Towards the end of my stay in Bangalore, as failure followed failure, I was
naturally forced to reconsider the whole basis of my work. But no; the most
critical examination of Manson’s induction failed to exhibit any flaw in the
fundamental reasoning. The gametocytes, and the process by which the mo-
tile filaments escape from them after the blood is drawn from the patient,
could only be meant for infection of the mosquito. There was no other ex-
planation. Nature does not create these complex phenomena for nothing; and
the theory must be - was - sound. What then was the cause of my repeated
failures? Was it possible that the kinds of mosquitoes which I had tested hith-
erto - very many kinds - were all of the wrong species?
The reasons for and against this view were as follows. In all the districts and
towns of India in which I had served or stayed during fifteen years - Madras,
Bangalore, Moulmein, the Andamans, Secunderabad, Upper Burma, Bom-
bay, Poona, Calcutta, Karachi, Quetta, the Nilgherry Hills, malaria was un-
doubtedly present, especially among the natives ; and in all of them without
* Not once as yet had I come across the dappled-winged mosquitoes ; though, be it noted,
many of my larvae were collected from ditches and the edges of ponds.
48
1 9 0 2 R.R OS S
exception I remember to have noticed mosquitoes belonging to both the grey
and the brindled classes. This naturally suggested a connection between the
disease and the insects; but, on the other hand, were not the later perhaps too
common? So far as I could ascertain, the disease was generally limited to cer-
tain spots and localities (by no means always near marshes); whereas the in-
sects were everywhere, and were indeed often commonest at points were ma-
laria was rare, as in the houses of Europeans. After all may not the true malaria-
bearing variety or varieties have been overlooked by me? Possibly they were
comparatively rare species, or species occurring only at a certain season - a
hypothesis favoured by the well-known fact of the seasonal variation of ma-
laria. Now, as I was fully aware at the time, malarial fever is a relapsing disease
in which attacks continue to occur for years after infection; so that it does not
follow by any means that the infective variety of mosquito must always be
present in a locality, even though numerous cases of malarial fever are present.
And it was to be specially noted that most of the cases occurring in Bangalore
were probably only cases of relapse.
These arguments were not strong enough to be conclusive on either side of
the question. I had done quite right in spending so much time over the grey
and brindled mosquitoes; there was enough prima facie evidence against them
to demand a full enquiry. But before spending more time over them it was
now advisable to see whether further light could be obtained by epidemiolog-
ical investigation. The towns in which I had worked hitherto could scarcely
be considered more than moderately malarious; I now proposed to visit an
intensely malarious spot, at the height, too, of the malarious season in order
to ascertain what kind of mosquitoes prevailed there at the time; and reason-
ably hoped that this kind would prove to be the guilty species.
Being a servant of Government I could not of course go where I pleased
without leave, and I therefore first attempted to interest Government in my
work. Owing to my representations, the United Planters’ Association of
Southern India took up the matter; and the Honourable Mr. Bliss, Member of
Council of the Madras Government, and also Surgeon General Sibthorpe,
head of the Madras Medical Service, were kind enough to give their warm
assistance - for which I shall always be much indebted. The result was that the
Government of Madras made a proposal to the Government of India that I
should now be placed on special duty to investigate malaria. Most unfortu-
nately, however, in addition to the plague, the Afridi war broke out just about
that time, and owing to the paucity of medical officers the Government of
India was obliged to reject the proposal - May 1896. But in the meantime I