DEVELOPMENT OF THE BACTERIA. 133 
quently we cannot invoke the movements of the 
liquid in order to explain their division. The 
bacteria of charbon, then, take but little oxygen 
from the tissues: they do not vegetate luxuriantly 
in the organism; and certainly, if we judge by a 
calculation necessarily approximative, their devel- 
opment is seven or eight times less rapid than in 
the strongly oxygenated serum of culture experi- 
ments (Toussaint). 
Polymorphism. — The spores of which we have 
traced the genesis constitute those germs of which 
the origin has for a long time been misunder- 
stood, — those permanent spores or durable spores 
(Dauersporen), thus called because of their re- 
markable degree of resistance to temperature, 
desiccation, and all the agents which kill adult 
bacteria or arrest their development. 
These “ organs” are disseminated in great num- 
bers in various media under the form of little 
rounded corpuscles absolutely similar to the micro- 
cocci from which it is absolutely impossible to 
differentiate them. It is, indeed, very probable 
that the greater part, if not all of these organisms, 
are the spores of filiform bacteria. 
In the impossibility of recognizing these forms 
so nearly related, of referrmg them to such or 
such a determined organism, the attempt has been 
made to cultivate them, in order to follow their 
development. We have just seen the results of 
this cultivation for the Bacillus ; but, in the hands 
of the greater number of experimenters, the re- 
