INFLUENCE OF DISEASE UPON MILK 107 
upward, producing a hard firm area (“ cake,” “ caked 
udder,” “cold garget”’), which may eventually involve 
the entire quarter. The newly formed connective tissue 
subsequently contracts and causes atrophy of the gland 
tissue and loss of function. 
In the early stages of the disease, and also throughout 
mild cases of mucous catarrh, the milk does not show any 
marked change at the time it is drawn from the udder. 
Very often it contains small flakes, some of which may 
be as small as a pin-head; they may be present only in 
the first milk drawn, but sometimes they do not appear 
until the middle or at the end of the milking. After the 
milk stands for a time, or is centrifugalized, a grayish- 
yellow sediment is deposited and a dirty-gray, clumpy 
or granular cream layer is formed. In severe cases of 
mucous catarrh, the secretion becomes slimy and viscid. 
In purulent catarrh, the secretion of milk decreases 
while the pus cells and fibrin increase and the fluid ob- 
tained from the affected quarter gradually changes to 
a thick, yellowish, purulent exudate or to a yellowish 
serum containing clumps of pus and fibrin. Frequently, 
the exudation ceases entirely and the milk secretion does 
not return until the next lactation or not at all. The 
chemical composition of the milk is only slightly changed 
at the beginning of the disease, the lactose being de- 
creased and the mineral salts, especially the sodium chlo- 
ride, increased, while the other constituents are present 
in the usual amount. Later, there is a greater decrease 
in the lactose, the casein is also below normal, and the 
fat is usually decreased, while the albumin, globulin, and 
mineral salts are increased. Fibrin is also present. The 
reaction of the milk is usually, but not always, alkaline. 
The taste is salty or bitter. Cells are present in large 
