22 MORPHOLOGY. 



spore-forming varieties (anthrax, megatherium), and in others it can 

 be shown that they have nothing to do with spores. They are there- 

 fore granules of unknown rank. 



2. Antecedents of spores {Bunge's granules). Small granules, usually 

 occurring multiple in sporulating cells, not staining according to 

 Ernst's method, but, on the contrary, in boiling Loffler's solution. 

 They are best shown, after previous treatment of the dried preparation 

 with chromic acid, sodium peroxid, or hydrogen peroxid, according to 

 the ordinary spore staining. (See Technical Appendix. ) The per- 

 fected spores are formed by the union of many small antecedents. 



Bunge explains the controversy which has occurred as due to much 

 confusion regarding the two varieties of granules. 



Regarding the cell=membrane, it is especially to be re- 

 marked that it often appears somewhat swollen, and not 

 sharply outlined from without. In many bacteria ("cap- 

 sule=bacteria" of authors) the thickening of the membrane 

 or its outer layer is so extreme that the bacteria appear 



i 



i 



Bacterium pneumoniae Bacillus anthracis Streptococcus lanceo- 



(Friedlander). (Cohn). latus (Gamal.). 



Fig. 5. — Capsule-formation (schematic). 



surrounded by a true mucous envelope or capsule, which 

 is distinguished by its slight staining property with anilin 

 dyes. It is an interesting fact that most of these capsule- 

 forming bacteria only form these envelopes if growing either 

 in the animal body or upon very special media, — fluid 

 blood-serum, bronchial mucus, and also, according to Paul- 

 sen, upon milk. 1 Upon gelatin, agar, and potato, nothing 



1 Whether exquisite capsule-formation always occurs on these nutri- 

 ent media, appears undecided. Recently, also, various authors have 

 pointed out that capsule=Iike formations can be demonstrated in a 

 wider field in the bacterial kingdom. Johne has described a method 

 (see Technical Appendix) for anthrax by which the capsule can be 



