134 PHYSIOLOGY OF THE BACTERIA. 



suits of such culture experiments are far from 

 being so certain. Not having succeeded in re- 

 moving them completely from the invasion of for- 

 eign germs, the greater number have seen the 

 most diverse forms develop themselves, and from 

 this have inferred the most remarkable transfor- 

 mations. 



Thus, Hallier pretends to have observed the 

 transformation of Micrococcus into various fungi, 

 such as Mucors, Ustilago, etc. The M. of vaccinia 

 comes from Torula rufescens, which is itself a 

 phase of development of Ustilago carbo ; the M. 

 of human variola is derived from a fungus having 

 sporangia and pycnidia, related to Stemphylium 

 sporidesmium ; that of the variola of animals 

 from Cladosporium (Pleospora) herbarum ; the 

 M. of the blood of scarlatina belongs to the 

 g. Tilletia ; those of glanders and of syphilis 

 from a Coniothecium, etc. In the same way Letz- 

 erich has referred the M. of diphtheria to another 

 Tilletia, the T. diphtherica. 



The transformation of bacteria into " levures " 

 (yeast fungi), and these into Penicillium, has been 

 admitted by Hallier, Trecul, and others. But the 

 researches of Brefeld and de Seynes have shown 

 us that this is far from being demonstrated ; in- 

 deed, in his numerous cultivations, de Seynes has 

 never been able to verify such an affiliation ; and 

 Nageli in his turn has never been able to obtain 

 a transformation of schizomycetes into budding 

 fungi. 



It is the same as regards the transformation of 



