CLASSIFICATION OF THE BACTERIA. 73 



They are divided into two categories, accord- 

 ing as the pigment is soluble or not in water. 



1. Coloring matter insoluble. 



M. Prodigiosus, Cohn (Monas prodigiosa, Ehrb. ; 

 — Palmella prodigiosa, Mont. ; — Bacteridium 

 prodigiosum, Schroeter). 



A red gelatinous mass, pink carmine, develop- 

 ing upon cooked alimentary substances placed 

 in damp air, never before cooking. 



It has also been observed in red milk, at- 

 tributed incorrectly to lesions of the teats, 

 etc. (Cohn). 



M. luteus, Cohn {Bacteridium luteum, Schroeter). 

 A yellow gelatinous mass studied by Schroeter 

 and Cohn upon potatoes. 



2. Coloring matter, soluble. 



M. aurantiacus, Cohn {Bacteridium auriantiacum, 

 Schroeter). 



Little drops, or stains, more or less extended, 

 golden yellow, cultivated by Schroeter, upon 

 slices of cooked potato; by Cohn, upon hard 

 white of egg. 



M. chlorinus, Cohn. 



A glairy yellowish-green pigment found upon 

 hard white of egg, not reddened by acids, but 

 loses its color. 



M. cyaneus, Cohn (Bacteridium cyaneum, Schroe- 

 ter). 

 Pigment deep blue, observed by Schroeter 



