202 
THOMPSON YATES LABORATORIES REPORT 
researches, both in general bearing and in detail, has been afforded by the observa- 
tion of the fertilisation process in the case of halteridum of birds (Haemamoeba 
danilewskii), as well as of human aestivo-autumnal parasites {Haemomenas praecox) 
by MacCai.lum, 6 and further of the formation of the ' vermicule ' in the case of 
proteosoma of birds (H. relicta\ by Koch, 7 and in the case of human malaria by 
Grassi, 8 who also observed by histological processes the passage of the 'vermicule' 
through the epithelial lining of the stomach of the mosquito. 
The Italian pathologists and zoologists, Bastianelli and Bignami, 9 Celli 10 
and Grassi," and others having peculiar facilities and opportunities for research 
in the subject in Italy, have contributed many confirmatory articles, and also by 
considerable experimental work have brought forward evidence which exculpates 
mosquitoes of the genus Culex from any part in the transmission of human malarial 
fever. 
The interesting experiment of Manson and Thorburn, 12 who, in London 
last year, allowed themselves to be bitten by mosquitoes infected from a case 
of tertian fever in Italy, and after fourteen days acquired a typical attack, exhibiting 
tertian parasites in the blood, afforded a strikingly conclusive confirmation of the 
work of Ross and of Italian observers. 
These discoveries naturally opened up the question as to how the results 
obtained might be turned to practical account for the prevention of malarial fever, 
so that commissions and expeditions were despatched to the tropics to ascertain at 
what period of the life-history of the parasite in man and in the mosquito the para- 
site is the most vulnerable, and how the attack might best be delivered. 
In 1899 there were sent out a German Commission under Professor Koch 
in German East Africa, a Royal Society's Commission to British Central Africa, and 
the expedition to West Africa from the Liverpool School of Tropical Medicine under 
Major RoSi. In 1 900, another German Commission, under Professor Koch, was 
despatched to the East Indies ; the Royal Society's Commission visited West Africa, 
and a second expedition from the Liverpool School of Tropical Medicine was sent to 
West Africa. 
Objects of the Expedition. — The experience of Major Ross in India, and the 
consideration of the results of his work, led to the conclusion that the parasite could 
be most easily attacked during its life in the mosquito, and as there was considerable 
evidence to exclude mosquitoes of the genus Culex from taking any part in the 
transmission of malarial fever, the first expedition of the Liverpool School of Tropical 
Medicine, of which one of us was a member, was undertaken to study the bionomics 
of mosquitoes of the genus Anopheles, with a view to suggesting better modes of 
prevention of malarial fever than those hitherto known to us. 13 As to the conclusions 
arrived at and the methods suggested, these will be found fully described in the 
report of the expedition.' 4 
