REPORT OF THE MALARIA EXPEDITION 
OF THE 
LIVERPOOL SCHOOL OF TROPICAL MEDICINE 
AND MEDICAL PARASITOLOGY. 
I. PRELIMINARY. 
I. — Introduction. — The Hjemamcepadj^. are a group of unicellular parasites of the 
red blood-corpuscle, found in man and in certain kinds of monkeys, bats, birds, and, perhaps, 
frogs. The group derives great importance from the fact that tlie human species are the 
cause of malarial fever. 
We owe the discovery of these organisms to Laveran, Danilewsky, Koch, and Dionisi ; 
and are indebted to Laveran, Golgi, Romanowsky, MacCallum, and otiiers tor our knowledge 
of their life-history and structure within the vertebrate hosts. 
Following upon these discoveries, it remained to ascertain the lite-history of the group 
outside these hosts ; but all efforts to cultivate them or to find them in cxterjial nature were 
attended at first with failure. In 1883, however. King adduced a number of reasons in 
support of the view that gnats are connected with the propagation of malarial fever [i]. 
Next year Laveran expressed the opinion that the parasites discovered by him may undergo 
further development in gnats [2]. In 1894 Manson independently came to the same con- 
clusion ; chiefly on the ground that some forms of the parasites (gametocytes) emit certain 
motile filaments (microgametes) after the blood containing them is drawn from the host a 
phenomenon which could be explained only by the theory that the parasites migrate into 
suctorial insects [3, 4]. Koch, Mendini, and Bignami have also adopted the gnat-theory of 
malaria on various grounds [12]. 
Working in India upon Manson's induction, one of us, after numerous negative 
experiments with several species of gnats of the genus Cu/ex, succeeded in cultivating one of 
the human Haemamoebidae in two species of gnats of the genus Anopheles (dappled-wintjed 
mosquitoes) in 1897 [5] ; and next year completed our knowledge of at least one cycle of 
the life-history of this group of parasites by following the development of Hcemamoeba relicta 
of birds in gnats of the Culex pipiens type [6], and by communicating the infection from 
diseased to healthy birds by the bite of these insects [7]. This work was confirmed by 
Daniels in 1898-99 [8]. 
A 
