130 PHYSIOLOGY OF THE BACTERIA. 



there is formed in each article so nourished a 

 spherical or ovoid spore, homogeneous, highly 

 refractive, having a dark outline. At the same 

 time, the protoplasm which occupies the rest of 

 the cavity disappears little by little, and is re- 

 placed by a hyaline liquid, which separates the 

 spore from the membrane ; this dissolves in its 

 turn, and finally the spore is set at liberty. If the 

 article is swollen in tadpole shape, it is in the ter- 

 minal swelling that the spore has birth ; if it is 

 spindle-shaped, it is near the middle ; if it is cylin- 

 drical, it may be at any point whatever, but is 

 usually near one extremity. The spore when set 

 free germinates under favorable circumstances. 

 At a point where its circumference becomes pale, 

 it gives out a little tube slightly more slender 

 than itself, which elongates rapidly and divides. 

 This fourth period of development or germinative 

 phase brings us back to our point of departure." 



Sporangia. — Finally, not only do the bacteria 

 develop spores in the interior of their filaments, 

 slightly modified in form, but we may also observe 

 the formation of a veritable sporangium contain- 

 ing many spores. The unpublished observations 

 of M. Touissant, Professor of Physiology in the 

 Veterinary School of Toulouse, give this result, 

 which he has kindly communicated to me. 



In cultivating spores of the bacteria of charbon 

 in the serum of the blood of the dog, under the 

 microscope, in the warm chamber of Ranvier, 

 Toussaint has seen the filaments take a transverse 



