126 



Notes, Communications and Reviews. 



an elementary work, written in a clear straightforward style, 

 and as free as possible from the burden of technicalities. 



The first chapter, of some eighteen pages, is devoted to intro- 

 ductory remarks on the Protozoa and the different classes into 

 which they are divided, together with some general observations 

 on their role in relation to disease. Chapter 11. is given up almost 

 entirely to sleeping sickness and its causative agent Trypanosoma 

 gamhiense. This parasite (Fig. 1) belongs to a group of 

 Protozoa which are actively motile organisins living, so far as we 

 know, entirely in the blood of vertebrates. It is carried from 

 one human being to another by the agency of Diptera of the 

 genus Glossina, which are commonly known as " Tsetse flies." 

 So far only one species, Glossina palpalis, has been clearly 

 implicated but it is improbable that it is the only one concerned 



n,-/- 



FlQ. 1. — Trypanosoma ganibiense, from Blood. 

 (Published by permission of the Authors and Publishers.) 



in this nefarious business. The remainder of the chapter deals 

 with a recently discovered t parasite — Schizotrypanum cruzi, 

 which brings about heavy mortality among children in South 

 America. This organism is carried from one child to another 

 through the bites of an Hemipterous insect known as Conovhitms 

 megistus which is common in houses. The third chapter opens 

 with an account of " nagana," a dreaded disease of domestic 

 animals in Africa. It is allied to sleeping sickness in man, the 

 pathogenic organism is also a species of Trypanosoma — {T. 

 hrucei) and it is, furthermore, disseminated from diseased to 

 healthy animals by the bites of another species of " Tsetse 

 fly" — Glossina morsitans. Mention is made of several other 

 species of Trypanosoma, including that of " surra," which is a 



