AND ZYGOTES IN MOSQUITOS INFECTED WITH MALARIA. 
PROBLEMS CONCERNING THE INrrcTION or MoOSQUITOS WHICH NEED 
FURTHER INVESTIGATION. 
1. Bodies of uncertain significance found in the Salivary Glands of 
various Mosquitos. 
(a.) In a large Anopheline (Myzorhynchus ? sp.), a species not frequenting 
houses, caught in the bush in Sierra Leone at a considerable distance from 
human habitations, sporozoits were found in one out of four examined. The 
nature of these is unknown, and further observations are much needed. 
(b.) The examination of specimens of an undetermined species of Caulew at 
Mabang, Sierra Leone, showed that 10 per cent. contained bodies resembling 
sporozoits, but more slender, twisted and irregular in outline. Some of these 
Culicines had fed on human blood, others were caught in the bush, Here again 
we have no knowledge as to the nature of these bodies. 
(c.) In another undetermined Culex, 5 to 10 per cent. of the specimens 
contained straight bodies in the globules of salivary secretion. ‘These resembled 
sporozoits, but were probably crystalline in nature. 
2. Alleged transmission of Malarial Infection through the Eggs of the 
Mosquito.—Statcments have been made, without a vestige of proof, that such 
transmission occurs. It may be well, therefore, to examine the eggs of 
Anophelines for sporozoits. Even should infected eggs be found, it would not 
be clear how they could transmit infection to the adult mosquito hatched from 
them, as there is no evidence that the sporozoits multiply or undergo further 
development in the mosquito. If we suppose that hereditary transmission does 
occur, the form of the parasite may be quite different from anything we know. 
Hence the study of the contents of normal eggs is of importance. 
3. What are the conditions which determine successful infection of 
Anophelines fed on malarial blood ?—In feeding experiments only a certain 
percentage are as a rule successful. In experiments made by Christophers and 
myself in India we got no result until we kept the Anophelines in a hot 
incubator, though in the villages they were naturally infected. Is it quite 
certain that no Culicines can transmit malaria ? 
4, How many persons can one Anopheline infect ?—We have no data on 
this point. In the case of Culicines the brothers Sergent have shewn that an 
infected Culicine can infect two, but not three consecutive birds with Proteosoma. 
Similar experiments might be made in the case of Anophelines and man, but in 
case this is not possible the experiments should be made with Culicine sporozoits 
on birds ; and, indeed, if opportunity ofters, bird-malaria still affords a fruitful 
field of research. In the greater part of Africa, however, Proteosoma does not 
exist, but in the mode of transmission of Halteridium, Haemogregarines, &c., 
there is abundance of work to be done. 
4. Does the percentage of infected Anophelines vary from month to 
month, and if so, to what extent ? 
5. How long does an Anopheline once infected remain so ? 
