292 PRINCIPLES AND PRACTICE OF MILK HYGIENE 



continues high for a time after the clinical symptoms 

 have disappeared. The increase of catalase in mastitis 

 is not always due to the bacteria present. Koning has 

 demonstrated that the streptococci of mastitis do not pro- 

 duce catalase, but that the toxins they excrete irritate 

 the gland tissue and cause an increased transudation of 

 blood serum and emigration of leucocytes, thus increas- 

 ing the catalase in the milk. The catalase may also be 

 increased in purely traumatic or non-bacterial mastitis. 

 When only one quarter of an udder is visibly diseased, 

 the milk from the other quarters which are apparently 

 healthy may show a high catalase reaction. The catalase 

 test cannot be relied upon to discover mastitis when mixed 

 milk is examined. Mixed milk containing 5 per cent, 

 of milk from a diseased udder will show a high oxygen 

 reading, but if the dilution is greater than this there will 

 be nothing abnormal in the reaction (Gerber) . 



In general disease, and when disease is present in 

 other organs than the udder, the oxygen reading of in- 

 dividual milk is usually, but not always, high. In these 

 conditions, according to Mogendorff, the catalase in the 

 milk is increased when the udder assists in the elimina- 

 tion of the products of disease, the toxins or other disease- 

 products irritating the gland tissue and causing an un- 

 usual amount of blood serum and leucocytes to pass over 

 into the milk. The presence of pathological processes in 

 the.body is often indicated by an increase in the catalase 

 in the milk before they are manifested by clinical symp- 

 toms, while in diseases in which resolution is not complete 

 the catalase may be increased in the milk after all clinical 

 symptoms have disappeared. As a rule, there is an in- 

 crease of catalase in the milk in all diseases accompanied 

 by a high fever; when non-encapsulated purulent areas 



