A HISTORY OF SCIENCE 



chicken cholera do not, in effect, seem to resolve them- 

 selves, in their culture, into veritable germs. The 

 latter are merely cells, or articulations always ready 

 to multiply by division, except when the particular 

 conditions in which they become true germs are known. 



" The yeast of beer is a striking example of these cell- 

 ular productions, being able to multiply themselves 

 indefinitely without the apparition of their original 

 spores. There exist many mucedines (Mucedineae?) of 

 tubular mushrooms, which in certain conditions of 

 culture produce a chain of more or less spherical 

 cells called Conidce. The latter, detached from their 

 branches, are able to reproduce themselves in the form 

 of cells, without the appearance, at least with a 

 change in the conditions of culture, of the spores of 

 their respective mucedines. These vegetable organ- 

 isms can be compared to plants which are cultivated 

 by slipping, and to produce which it is not necessary 

 to have the fruits or the seeds of the mother plant. 



" The anthrax bacterium, in its artificial cultivation, 

 behaves very differently. Its mycelian filaments, if 

 one may so describe them, have been produced scarcely 

 for twenty-four or forty-eight hours when they are seen 

 to transform themselves, those especially which are in 

 free contact with the air, into very refringent corpus- 

 cles, capable of gradually isolating themselves into 

 true germs of slight organization. Moreover, observa- 

 tion shows that these germs, formed so quickly in the 

 culture, do not undergo, after exposure for a time to 

 atmospheric air, any change either in their vitality or 

 their virulence. I was able to present to the Academy 

 a tube containing some spores of anthrax bacteria pro- 



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