DEVELOPMENT OF THE BACTERIA. 115 



above all the hydrates of carbon and their deriv- 

 atives ; and in this respect they resemble animals." 



Absorption. How are these various substances 

 absorbed ? The observations of Grimm, Hoffmann, 

 de Seynes, etc., permit us to assure ourselves that 

 these organisms absorb by endosmosis the sub- 

 stances upon which they are nourished. 



Grimm, upon examining with the microscope 

 some particles of lemon containing bacteria and 

 spores of algae, saw a certain number of the former 

 gather around a spore, and fix themselves to it 

 by one of their extremities. They did not pene- 

 trate it; but when they abandoned it, the spore 

 had diminished in volume, and lost a portion of its 

 contents, while the bacteria had taken a greenish 

 color. 



Hoffmann has seen that these little organisms, 

 when placed in a solution of carmine or of fu- 

 schine, after a time are colored an intense red, 

 while the mucus surrounding them remains color- 

 less. 



De Seynes, also, from his observations upon 

 the vibrios which accompanied some colored fila- 

 ments of Penicillium glaucitm, believes that bacte- 

 ria are susceptible of absorbing coloring matters 

 from vegetables and from animals with which they 

 are in contact. 



Oxygen. The role of oxygen in the life of the 

 bacteria has given rise to numerous controversies. 

 First, it seems a priori that the bacteria ought 



