42 MILK HYGIENE 



9. Exercise and work. According to a number of 

 different experiments at hand (Dolgich, Torssell, and 

 several others) daily exercise increases milk secretion 

 so that not only the amount of milk increases, but also 

 the total quantity of fats. Sometimes, indeed, the per- 

 centage of fat increases, and, as a rule, the percentage of 

 casein diminishes, while the other constituents are 

 affected irregularly. 



Work does not necessarily influence the milk secre- 

 tion to a great degree (Morgen), but generally causes a 

 slight diminution in quantity and there is an increase in 

 the percentage of fat and a proportionate but smaller 

 increase in the percentage of protein and ash. Exhaust- 

 ing work causes not only a material decrease in the 

 quantity of milk, but also a disturbance in the whole 

 secretion, so that even vegetable fats are excreted in 

 the milk in unchanged condition (Dolgich). 



10. Disease of the cow often brings about a decrease 

 and sometimes even an entire cessation of the milk 

 secretion. In diseases of the udder, the milk under- 

 goes, as will be seen later, very important chemical 

 changes. There is very little positive knowledge of 

 the changes in the composition of milk during diseases 

 that are not localized in the udder. Apparently, it is 

 usually the rule that the daily variations in the composi- 

 tion increase, or, in other words, that the secretion is 

 thrown out of equilibrium. Frequently, in the beginning 

 of disease, there is found an abnormally large pecentage 

 of fat that results from the often sudden decrease of the 

 quantity of the secretion. A salty taste which occurs not 

 infrequently, might possibly mean an increase in the 

 quantity of protein and ash (secretion of blood serum). 

 According to long-standing opinion, milk has an abnor- 

 mal taste in cases of indigestion of all sorts and under 

 these conditions it also curdles easilv. 



