222 IMPORTANT VARIETIES OF FISSION-FUNGI. 



This variety, first isolated from the milk-stools of in- 

 fants by Escherich, is, according to our investigations, and 

 according to Escherich' s own statements, to be differenti- 

 ated from the Bact. acidi lactici merely by the absence of 

 staining by Gram's method 1 — a characteristic upon which 

 no great value can be placed according to recent experiences. 



A further difference, which Escherich understands from 

 Hiippe's description, that Hxippe's organism was an obli- 

 gate aerobe, we cannot recognize according to our investi 

 gations as present, for as often as we isolated the Bact. 

 acidi lactici from sour milk in Wiirzburg, it always pro- 

 duced fermentation anaerobically. We cannot place any 

 great value upon the luxuriant, sometimes hemispheric, 

 slimy growth upon the surface in the gelatin stab, which 

 he likens to the growth of the Bact. pneumonias. Escherich 

 has even seen exceptions. 



Metabolic Products. — Alcohol, acetic acid, active lac- 

 tic acid, succinic acid, and, according to Nencki (C. B. x, 

 82), also CO 2 and H. According to Smith, about 30%- 

 40% C0 2 , 60%-70% H. Indol is not produced. 



For us Bact. lactis aerogenes is the name for a form 

 without flagella, parallel to the typical peritrichous Bact. 

 coli, or for a Bact. acidi lactici which is not stained by 

 Gram's method. Transition forms certainly may exist, — 

 compare remark 1, — but one proved to be well founded is 

 not certainly known to us. Very closely related is the 

 Bact. diatrypeticum casei Baumann (C. B. xiv, 494), 

 which is widely distributed in milk, water, and soil, and 

 causes the cavities in cheese, or perhaps aids in their for- 

 mation. Composition of gas : 63% C0 2 , 37% H 2 . It is 

 provided with a capsule. 



We can see no final proof in the investigations of 

 Scheffer (A. H., 1897, xxx, 291) by which he attempts 

 to make a distinction between the two varieties dependent 

 upon immunization and agglutination experiments, for we 

 remember that the different varieties of the streptococcus 

 furnish no reciprocal immunity, and that each form of the 

 Bact. coli furnishes a serum which strongly agglutinates 

 only the form concerned. 



1 Wiirtz and Lendet find both varieties identical. 



