128 PHYSIOLOGY OF THE BACTERIA. 
Cohn, who had in his first publications refused 
to the bacteria the property of reproduction by 
spores, thinking that the facts observed by Hoff- 
mann related to different beings, has verified the 
experiments of Koch upon the development of 
B. anthracis, and has himself demonstrated sim- 
ilar phenomena in ZB. subtilis. 
In culture experiments made with infusion of 
hay, we see, at a certain moment, in the homo- 
geneous filaments of the Bacilli very refractive 
corpuscles making their appearance. Hach of 
them becomes a spore, oblong or in the form 
of a short filament, highly refractive, and with 
well-defined outlines. We find the spores ar- 
ranged in a simple series in the filaments. As 
soon as the formation of spores has terminated, 
the filaments can generally no longer be distin- 
guished, and one would say that the spores were 
completely free in the mucus; but their linear 
arrangement shows always that they are produced 
in the interior of filaments. Little by little these 
dissolve, being reduced to a fine powder; and the 
spores fall to the bottom of the liquid, where they 
are found in abundance. The germination of the 
spore does not seem to occur in the same medium; 
but if we take a spore from the deposit formed in 
an infusion of boiled hay, and transport it into a 
new infusion, we see the spore swell up, and a short 
tube form itself at one of its extremities: at this 
moment it resembles a bacterium with a _ head. 
Soon the very refractive body disappears, the tube 
stretches out into a short rod of Bacillus, com- 
