MORPHOLOGY OF BACTERIA. 71 



Migula arrived at the same conclusions from a study 

 of the very large bacillus oxalaticus, a sporulating 

 variety related to the hay bacillus. He emphasizes 

 particularly the fact that he has never succeeded in 

 staining the "central body" darker than the proto- 

 plasm. In the protoplasmic tube which has been 

 squeezed out of the cell membrane, the central space 

 for the fluid can be made especially distinct by the 

 fact that in media which abstract water it becomes 

 smaller ; in water it becomes larger. 



In very many varieties the interior of the bacterium 

 cells is found, after suitable staining, to contain pecu- 

 liar granules. Babes, their discoverer, applied to 

 them the non-committal term metachromatic gran- 

 ules (i.e., staining differently than the body of 

 the bacterium), while Ernst, their first thorough 

 investigator, terms them nuclei or sporogenous 

 granules. 



For the literature, which is rich in controversy, 

 I refer to Babes (Z. H., XX., 412), and here will 

 merely give the very plausible and clear views of R. 

 Bunge, the most recent student of the subject. Bunge 

 (Fort. d. Med., XIII., 1895) distinguishes: 



1. Ernst's granules. They are stained by warm 

 Loffler's methyl blue, and are differentiated black- 

 ish blue by a solution of Bismarck brown ; but they 

 disappear on boiling. These granules are entirely 

 absent in some sporulating varieties (anthrax, mega- 

 therium) ; in others it can be proven that they have 

 no relation to spores hence they are cell granules of 

 unknown rank. 



2. Sporule preliminary stages (Bunge 's granules). 

 Small granules, the majority of which are usually 



