264 IMPORTANT VARIETIES OF FISSION-FUNGI. 



This variety corresponds, except in the liquefaction of gelatin, to a 

 Bact. lactis aerogenes. 



We obtained this variety twice from Zimmermann, once marked 

 Bac. disciformans, the second time Bac. azureus. The varieties corre- 

 sponded in no way with the description which Zimmermann gave 

 them, but, on the contrary, the two were identical even in the smallest 

 details. 



Bacterium punctatum. (Zimm.) Lehrrs. and 

 Neum. 1 



Synonym. — Bacillus punctatus Zimm. (i, p. 38). 



Short rods (0.8 // long, 0.5 // thick), often also forming long threads. 

 Actively motile from one polar flagellum. Not stained by Gram's 

 method. Superficial colonies are first roundish, smooth-bordered, 

 transparent, punctate disks ; gradually the border becomes finely 

 notched and finally presents beautiful hairy border (somewhat like 

 41, v). Simultaneously liquefaction begins as a shallow saucer, in 

 which the remnant of the colony can be seen at the center. The 

 border of the saucer is surrounded with a delicate grayish-white zone, 

 sometimes presenting sinuous decorations. The gelatin stab culture 

 at first resembles cholera, but liquefaction rapidly becomes complete. 

 Upon agar and potato the growth is not characteristic, resembling 

 that of the Bact. coli. Milk is coagulated and then the coagulum is 

 liquefied. Grape-sugar is actively fermented, with production of gas. 

 Abundant production of H 2 S and little of indol. According to 

 Kruse, this organism, for which he unfortunately suggested the super- 

 fluous name Bac. aquatilis communis, is one of the most common 

 water bacteria. It corresponds to a Bact. fluorescens without the 

 production of pigment. We have also obtained this organism very 

 frequently from water (if we leave out of consideration the fermenta- 

 tion of sugar, which we rarely tested), and also have often observed 

 forms which were colorless at first for a long time and then became 

 feebly fluorescent. 



We found the Bacillus annulatus Zimmermann (n, p. 30) very 

 similar in all morphologic and biologic peculiarities; nevertheless it is 

 very well distinguished by habitually producing liquefaction in gelatin 

 in the form of holes. The marked, white accumulation of bacteria 

 which is present beneath the undermined edges of the colonies in the 

 plate culture, the colonies looking as if cut out by a punch, gives a 

 very striking picture. 



Bacterium vitulinum. (Weissenberg.) L. and N. 



Short rods, motile, not staining by Gram's method, re- 

 sembling the Bact. coli. Facultative anaerobe. Young 



1 An organism, similar in every way, but not forming gas from 

 sugar, was isolated by us from gastric contents. 



