METHODS OF EXAMINING MILK 293 



are present in the body, as in traumatic pericarditis, ab- 

 scesses, f urunculosis, 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.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 2 ) will be 



