INFLUENCE OF DISEASE 



55 



trum in appearance and finally changing to a thick yellowish 

 secretion containing many dark flakes in a clear serum. 



In chronic infections the changes are gradual and the ap- 

 pearance and composition of the milk may be almost normal 

 for a tiine; sooner or later, however, the cell content is increased 

 with a consequent increase in the albumin, and erythrocytes 

 cause a discolouration of the sediment on standing. 



In udder infections the fat usually decreases but may fluc- 

 tuate rapidly within rather wide limits; the lactose and casein- 

 ogen usually decrease slightly, but the decrease in the latter 

 constituent is more than counterbalanced by a marked increase 

 in the albumin, resulting in an abnormally high proteid content. 



These changes result in very abnormal 



proteid 



and 



lactose 



fat proteid 



ratios as is shown in Table XXXII. On accovmt of the bac- 

 terial origin of these infections, the enzymes in the milk are very 

 much increased. 



Table XXXII 



EFFECT OF DISEASE ON COMPOSITION OF MILK 



(SCHAFFER AND BeNDZYNSKI) 



Another cause of abnormal composition of milk is the cessa- 

 tion of the lactation period. This has already been discussed 

 on page 49 where it was shown that during the last stages of 



lactation, the — —^ ratio decreased considerably owing to the 



increased proteid percentage. 



Milk Adulteration. Artificial abnormalities in the com- 

 position of milk produced by the addition of extraneous sub- 



