METHODS OF EXAMINING MILK 293 
are present in the body, as in traumatic pericarditis, ab- 
scesses, furunculosis, panaritium; in diseases of the diges- 
tive apparatus such as gastro-intestinal catarrh, constipa- 
tion, tympanites, enteritis, etc.; when the organs of elim- 
ination are affected, as in icterus, interference with the 
excretion of urine, constipation; in acute and chronic in- 
flammation of the uterus; in peritonitis, and in advanced 
tuberculosis, even when the udder is free from the disease. 
The catalase will also be increased in the milk of all cows 
reacting to tuberculin for several days after the injection. 
Whether a high catalase reaction is due to disease in 
the udder or to disease in another part of the body may 
be determined by centrifugalizing the milk and examin- 
ing the sediment. If the disease is in the udder, leuco- 
cytes will be present in excess of the usual number. 
Gratz and Naray observed that when the oxygen reading 
is high in the milk of cows which have recently “fresh- 
ened,” the sediment, as obtained by the Trommsdorff 
method, may be low in volume but of a red color, the high 
catalase reaction being due to the presence of red blood 
cells. For a time following parturition, red blood cells 
may enter the milk by diapedesis or by rupture of blood 
vessels. They therefore regard it as necessary to examine 
the sediment before deciding as to the cause of a high 
catalase reaction. 
Fresh market milk from cows in normal condition, 
which has been properly cooled and cared for, should 
never show over 4:¢.c. of oxygen at the end of the second 
hour (Gerber). When market milk shows a higher 
oxygen reading, the indication is that the original bacter- 
ial contamination has been excessive, or that the milk is 
old, or that it may have pathological milk or colostrum 
mixed with it. A large amount of gas (CO:) will be 
