364 
Micrococcus freudenreichii and two forms of streptococci, one the 
source of the slimy ferment in Holland, the latter present on the 
leaves of Pinguicula, the latter being employed in Norway as the 
source of the ferment ; and as pointed out by Beyerinck sliminess in 
milk may be produced by certain of the lactic-acid bacteria, espe- 
cially by those growing at low temperatures. Slimy milk also 
results from a diseased condition of the mammary gland and is a 
common characteristic of garget. Nothing is known of the chemical 
nature of the substances causing the sliminess of milk. 
Bitter milk. — Freshly drawn milk has sometimes a bitter taste, in 
other instances it acquires such a taste on standing a few hours. 
The bitter taste of freshly drawn milk is sometimes due to the passage 
of bitter substances into, the milk from the food of the cow, such as 
lupines. It may also be produced during the last stages of lactation. 
In those cases in which the bitter taste develops only after standing 
the cause thereof is to be sought in changes in the composition of the 
milk due to the action of certain organisms. A considerable num- 
ber of organisms seem to possess the power of producing a bitter 
taste in milk, some of them after a short interval, others only after 
a longer one. Only the former are of any practical significance in 
the dairy, and among these may be mentioned a micrococcus, a cut 
of which is shown by Conn, and a bacillus described by Weigmann, 
which have the power of ruining the taste of freshly drawn milk in 
a few hours. The source of these organisms is difficult to trace. In 
one case cited by Conn the organism giving rise to this abnormal fer- 
mentation was traced to the fnilk ducts of a single cow. 
Nothing is known regarding the chemical nature of the substance 
or substances resulting from the action of such organisms as accom- 
plish the bitter fermentation. 
The alkaline fermentation of milk. — It has been observed that 
boiled milk never turns sour by spontaneous fermentation. On the 
other hand, when boiled milk is allowed to stand at ordinary tem- 
peratures it gradually acquires an alkaline reaction, ofttimes a bit- 
ter taste, and finally curdles, yielding a soft, slimy curd. On further 
standing this curd gradually dissolves to form a somewhat clear 
liquid, and if the fermentation be allowed to proceed for a sufficient 
length of time a semitransparent liquid is obtained, having no resem- 
blance to milk. As with the other fermentations of milk, a number 
of organisms are capable of causing the alkaline fermentation of milk, 
and & considerablq number of substances are produced as the result 
of these changes. Among the substances found in milk which has 
undergone the alkaline fermentation may be mentioned the peptones, 
which are believed to be responsible for the bitter taste, leucin, tyrosin, 
and ammonia, which latter imparts to the liquid the characteristic 
alkaline reaction. Butyric acid is also formed in this fermentation. 
