BACILLUS HYSTOLYTICUS 549 
or fluids, are actively motile. The motion, which is undulatory in 
character, tends to disappear ui)()n ])rolonged artificial cultivation, and 
also in the later days of artificial cultivation of the organisms which 
were motile at the start. Weinberg and Seguin have demonstrated 
l)eritrichic fiagella attached to the bacilli, and these may be numerous. 
They state that even twenty or more may be demonstrated upon a 
single cell. Capsules have not been observed. 
Spores form readily in artificial media; they appear usually within 
twenty-four hours after growth becomes established. They are oval in 
outline, slightly greater in diameter than the vegetative cell, and are 
located either at the end, or very near the end of the parent rod. In 
the latter event, a small but perfectly distinct cap of protoplasm extends 
between the end of the spore and the end of the rod. 
The organism stains by Gram's method during the earlier hours of 
cultivation in artificial media, and the organism then appears very 
commonly and characteristically as a Gram-positive diplobacillus, the 
two elements being separated at their proximal ends with a slight, 
but distinct unstained band. As cultures grow older, the ability to 
retain the Gram stain is lost in part, or entirely, and degeneration 
forms make their appearance. These degeneration forms frequently 
stain poorly, even with ordinary anilin dyes, but they never assume 
the peculiar and characteristic shapes so distinctive of the degeneration 
of Yibrion septique. 
Isolation and Culture. — B. histolyticus grows with moderate luxuriance 
in ordinary cultural media under conditions of strict anaerobiosis, but 
development is more luxuriant in media enriched with protein, as 
gelatin, meat medium, or the brain-liver medium. HalP has succeeded 
in inducing aerobic growth of this organism. The colonies developing 
upon the surface of anaerobic agar plates are thin, somewhat irregular 
films with serrated edges. Adjacent colonies tend to become confluent. 
Submerged colonies are -conglomerate with flocculent out-growths in 
media which are not too dense. Colonies upon gelatin are not char- 
acteristic; usually the medium liquefies within twenty-four hours. 
Meat medium is rather rapidly digested, and bundles of fine white 
crystals are found among the products of digestion. These crystals 
have been regarded by some observers to be impure tyrosin, but they 
fail to give any of the chemical reactions of tyrosin. Coagulated serum 
is liquefied. 
Milk.—B. histolyticus acts rather energetically upon the casein of 
milk, first precipitating it as a fine, granular clot; this precipitation 
appears to be associated with a rather large accumulation of acid due 
in part to the formation of amino-acids from the protein constituents. 
Eventually, the casein coagulum is nearly dissolved, leaving a brown- 
ish, residual liquid with a few undigested casein floccules. 
The organisms do not ferment any carbohydrates. 
' Proc. Soc. Exp. Biol, and Med., 192:1. 20, .501. 
