2IO BACTERIOLOGY. 



septicaemia occurring in India among horses, 

 asses, and camels, is caused by flagellate monads 

 (Crookshank.) 



In 1882, Laveran proved that animal mi- 

 crobes were present in the blood of patients 

 suffering with malaria ; this microbe was 

 called Plasmodium malaria by Marchiafava 

 and Celli. Gerhardt has been able to cause 

 malaria in healthy men by transfusion of blood 

 containing these minute organisms, which are 

 certainly to be regarded as the exciting cause 

 of the disease. Attempts at cultivation have 

 not succeeded up to the present time, so that 

 the course of individual development must be 

 inferred from inspection of the different forms 

 in various stages of development. 



In the smallest disk-shaped forms, which, 

 however, can change their shape in an amoe- 

 boid fashion, the nucleus is large in pro- 

 portion to the cytoplasm ; in the older indi- 

 viduals the case is reversed ; the plasm of the 

 young forms is homogenous, that of the older 

 ones often granular. In the older forms there 

 is always found the black malarial pigment 

 which is called melanin and is supposed to be 

 the digested and altered haemoglobin. The 

 fully formed parasites develop flagella which 

 often break loose from the cell ; frequently the 

 flagella show knob-shaped swellings usually 



