186 MICROBES, FERMEN‘IS, AND MOULDS. 
they appear in increasing numbers, and their maximum 
corresponds with the beginning of the rise in tempera- 
ture; from that moment they begin to perish, since 
the heat of fever is fatal to them, ‘and completely 
checks their development. This explains the inter- 
mittent character of the disease. They produce fever, 
the fever kills them and then subsides ; when apyreaia 
occurs they multiply again, excite fever, and so on.” 
Thus there is a successive series of auto-infection by 
the parasite itself, unless its development is arrested 
by sulphate of quinine. “The parasites of typhus 
and typhoid fever are not affected by a temperature 
of 40°, and even of 42°, and hence the continuous 
character of these fevers.” 
Cornil has, with some justice, criticized Laveran’s 
description and illustrations of the parasite of marsh 
fever. It is difficult to recognize in it an organism 
really belonging to the animal or vegetable kingdom. 
The form of the filaments which, as he asserts, issue 
from the so-called encysted bodies, resemble those 
which Hoffmann has seen and drawn in blood in its 
normal state, and also in various diseases, and are 
probably only expansions of extravasated protoplasm 
in the red corpuscles at a temperature of 40°. The 
encysted bodies are also, according to all appearance, 
only blood-corpuscles, more or less affected by disease. 
There only remain the pigmented, encysted granules 
in the red and colourless corpuscles, granules which 
have been observed by others, and especially by 
