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, Schrceter). 



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, 

 Schrceter). 



Little drops, or stains, more or less extended, 

 golden yelloio, cultivated by Schrceter, 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 Schrceter 



