363 
fermentation induced by bacteria. Among the organisms known to 
produce this change in milk may be mentioned Bacillus erythrogenes, 
B. prodigiosus, and a sarcina. The production of red milk through 
the agency of bacteria is without practical significance. 
Other color changes in milk. — Still other changes have been found to 
occur in milk and practically all of the pigment-forming bacteria will 
develop their characteristic pigments in milk in the event that they 
gain access thereto. According to Conn (31) orange-colored milk, 
green milk, yellow milk, amber-colored milk, indigo milk, chocolate- 
colored milk, and black milk have all been described by bacteriolo- 
gists. In all cases the pigment has been found to have been produced 
by bacteria. These have been isolated and their morphological char- 
acteristics determined. Ordinarily they are not normal infections, 
and hence are of no practical importance in dairying. 
Slimy or ropy milk. — Under certain conditions, slimy, mucilaginous 
substances are produced in milk through the growth of certain 
organsims which impart to the milk a characteristic sliminess or 
ropiness. Milk possessing such properties is known as slimy or ropy 
milk. It often can be drawn out into long threads of exceeding 
fineness. For example, slimy milk has been obtained of such vis- 
cosity that it could be drawn out into threads 10 feet in length 
and of such fineness as to be scarcely visible. In certain countries 
slimy milk is esteemed as a delicacy, and special methods have 
been described for its preparation. Such is the case in Norway, 
where it is called by the natives “ taetamoelk.” In Holland also a 
special ferment is employed in the manufacture of Edam cheese, 
which has the power of rendering the milk slimy. The cheese made 
from such milk is said to ripen more rapidly and more evenly than 
cheese made without the use of this particular organism. This 
peculiar change in the consistency of milk has also been found to be 
due to bacteria and ordinarily, as it occasionally occurs in the dairy, 
is a source of great trouble and annoyance. Many bacteria seem to 
have the power of producing a slime in milk under suitable conditions. 
Ordinarily, however, this change is accomplished by one or two bac- 
teria having a wide distribution in nature. Of these B. lactis vis- 
cosus (Adametz) seems to be the commonest . organism of the kind 
found in Europe, and a similar organism, probably the same species, 
occurs in this country. It is a very hardy organism, and finds its 
way into the milk through the water supply of the dairy. From 
such a source the infection may become widely diffused and difficult 
to trace. However, it is an infection which, no matter how trouble- 
some, can be eradicated through cleanliness, although in certain 
instances' it, may be necessary to resort to disinfectants. Among 
other organisms producing sliminess in milk may be mentioned 
