ita STORRS AGRICULTURAL EXPERIMENT STATION. 
To this same group apparently belongs M7. Freudenreichii, as well as can be 
determined by the incomplete descriptions given. 
Reference must also be made to MM, Jactis viscosus B., differing from either 
of those described, so as to be located elsewhere in our scheme. (See p. 109.) 
The white cocci which produce acid and no slime are very numerous and their 
separation into groups is uncertain. We have tried to divide them into 
several types but the divisions between them are not satisfactory. Each of the 
groups shows variations, and it may be better to unite them altogether. For 
the present, however, we recognize the following divisions, based primarily 
upon their action on sugar and the abundance of their surface growth. 
S. lacticus Kruse. This includes the smaller acid cocci with a scanty surface 
growth. This type is very closely related to, if not identical with, Bact. lactis 
acidi, The organism that commonly causes the souring of milk shows some 
variation in its morphological structure. It is sometimes clearly a short coccus 
form, while in other cases it is decidedly more elongated. In cultures, too, 
similar variations have been found. It commonly appears as a short rod, 
clearly longer than broad, and as such has been usually described as a Bac- 
terium and named Bact. dactis acidi by Leichmann. By this name it is commonly 
referred to in literature. But cultures of Bac¢. dactis acidi when grown in lactose 
bouillon frequently, at least, appear as streptococci, and Kruse (Cent. f. Bac. 
u. Par. I., XXXIV., p. 737, 1903), and Heinemann (Cent. f. Bac. u. Par. II., 
XVI,, p. 538, 1906), have recently insisted that there is no such thing as Bact. 
lactis acidi, all of the organisms which have been so named being really cocci, 
which should be called S. /acticus. Upon this point we will at present express 
no opinion beyond the statement that the organisms as found in souring milk 
are sometimes streptococci and sometimes clearly longer than broad, and hence 
would be naturally classed as Bacterium. We regard it better at present, there- 
fore, to retain the name Bact. /actis acidi for the milk type as it commonly ap- 
pears, and to recognize the streptococcus form independently under the name 
given by Kraus It has the following characters: 
Morphology.—A streptococcus with commonly short, but sometimes long, 
chains. Size, .5u-1". Gram stain positive. 
Gelatine colony.—Extremely minute, white colonies, occasionally slightly 
yellowish, rough and dense. In ditmus gelatine the colonies are always acid. 
The surface growth is always slight and usually absent entirely, and it grows 
better under a mica plate. Sometimes the colonies in litmus gelatine show 
minute spines on their edge. 
Gelatine stab,— A moderate needle growth but no surface. 
Agar streak.—The growth is hardly visible, but when it occurs is the faintest 
transparent film. 
Fermentation tubes.—Al\ three types of sugar are rendered acid and there is 
commonly a growth in the closed arm. No gas is produced. 
Bouillon.—Growth is extremely slight and sometimes invisible. A slight 
sediment and turbidity may be produced. 
Milk.—Rendered acid and curdled promptly, producing a typical, smooth, 
acid curd. 
