
CLASSIFICATION OF DAIRY BACTERIA. 49 
Potato; growth is hardly visible. 
Bouillon; becomes very cloudy. 
Milk; is rendered acid, but the amount of acid is zasa ficient to curdle the 
milk unless it is heated. 
These two cultures appear to me to be new, and their characteristics are so 
marked that I have ventured to give them a name. 
No. 2. MW. acidt lactis, (Kriiger.) 
Morphology; 1m to 1.2m in diameter. 
Gelatin plate; at first a slight pit, which begins to liquefy, the colony being 
uniformly granular. The granules soon break up, distributing themselves 
through the pit, usually producing a nucleus, with a peripheral ring of granules. 
Outside the ring there may be a clear liquid outer zone. Eventually the whole 
becomes densely granular. 
Agar; growth on the surface tends to become wrinkled, tenacious and sticky, 
and develops a yellowish or slight sa/zon color. 
Potato; an abundant growth, somewhat folded, of a flesh or salmon color. 
Milk is curdled at 20° or at 36° into a hard coagulum, with orange masses 
floating on the top. The reaction is aczd. No digestion occurs. After a few 
days yellow lumps of fat frequently appear on the surface. Chemical analysis 
has shown butyric acid and alcohol to be present. 
The last three organisms are peculiar in éguefying gelatin, but curdling milk 
with an acid reaction. This is unusual. Three or four such micrococci have 
been described before by Hueppe, Freudenreich, Kriiger and Kozai. I have 
concluded that No. 2 may be the same as the species described by Kriiger and 
Kozai. 
GROUP VII. NON-LIQUEFYING, NON-CHROMOGENIC BACILLI. 
This group, which is the most important group of dairy bacteria, is a very 
difficult one to arrange in any satisfactory manner. ‘The different species are 
frequently very similar to each other, and the diagnostic characters difficult to 
determine. Iam convinced that in some cases quite different bacilli are put 
under the same species because of difficulty in getting diagnostic characters for 
separating them. 
I have found it most convenient to separate them, first in accordance with 
their power of producing an acid reaction in milk, and secondly in accordance 
with their morphological characters. A few are readily distinguished by their 
peculiar gelatin colonies, and some by their spore production. 
Division A. 
Bacilli producing an acid reaction in niulk, 
Nos. 125 and 89. B. colt communts. 
This species of bacillus is extremely common in milk, although by no means 
universally found. It seems to show considerable variation. T’he two num- 
bers above given are two of the many distinct cultures which I have identified 
with B. coli. They differ slightly. No. 125 shows gas bubbles in the gelatin 
