132 
Filariasis in Ceylon 
I collected the mosquitoes wherever I was able and I give at the end 
of this paper a list of localities in which different species were taken. 
Two species, Culexfatigans, and more especially Mansonioides uniformis, 
were abundant in all filaria-infected areas. I am inclined to regard 
the latter, relying solely on epidemiological grounds, as being the main 
filaria carrier in Ceylon, a subject worthy of further investigation. 
The few transmission experiments which I made with different 
anophelines, especially M. barbirostris, proved negative. 
The relation of malaria to filarial disease. 
I saw three cases of elephantiasis in a community heavily infected * 
with malaria and of whom 44 % had enlarged spleens and 22 % malaria 
parasites in their blood, and l - 8 % microfilariae. In the neighbouring 
town of Tangalla the microfilaria rate was found to be 8'8 %, the 
spleen rate nearly 99 %, and the parasite rate (mostly malignant 
crescents) to be 25 %. Arguing from these two instances there is no 
epidemiological evidence in favour of a supposition that the one 
infection militates against the other, or that the locally prevalent 
anopheline is incapable of transmitting both the malaria parasite and 
the filaria worm at the same time. 
Finally I submit that this investigation has shown 
(1) That of the four or five known species of filaria blood worms, 
only one of them, viz. F. bancrofti, is represented in Ceylon. 
(2) That its periodicity, as in the case with India, the West Indies 
and many other countries (but not in many of the Pacific Islands), is 
of a definitely nocturnal character. 
(3) That it is a rare parasite in the north and centre of the island, 
but a common one on the east and south coasts. 
(4) That in the endemic areas, the topographical distribution is 
apparently of a most capricious character. 
(5) That, whereas in some of the villages at least 26 % of the adults 
are infected, in the neighbouring villages the inhabitants are quite free 
from the parasite and its associated diseases. 
This latter circumstance suggests careful investigations into an 
apparent anomaly, for could an explanation of the liability to the para¬ 
site of one village community and the immunity of a neighbouring 
village be supplied, we might be placed in possession of knowledge 
which would enable us to control or eradicate a serious disease agency. 
Further, such an investigation might lead to or suggest an explanation 
