622 PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



milk if there is an insufficient amount of albumen given at the same 

 time. 



Carbohydrates in food of carnivora appear to be without influence 

 on amount of milk-sugar. Also, in herbivora, milk-sugar depends for its 

 origin principally on the albumen of the food. 



The mode of living is of the greatest influence on the milk secretion. 

 When a large quantity of milk is desired, the animals must remain per- 

 fectly at rest, as every excitement or movement, even of the animals' 

 body muscles, decreases the milk secretion. When the animals are per- 

 fectly motionless the greater, part of the blood-stream passes through 

 the glands, and vice versa. So a much smaller quantity of milk is pro- 

 duced by grazing than by stall-fed animals, and it has been found that 

 even leading cows out to drink decreases the amount of milk. 



The feeding has also a certain influence on the composition of the 

 milk ; to produce a large quantity of good milk, the animal, naturally, 

 must receive enough food to maintain a good condition. If a poor food 

 is given the milk will not be very seriously influenced, nor will a rich 

 food increase the quantity of milk to any great extent. The milk secre- 

 tion is far more closely dependent on the breed of cattle than on the 

 feeding; a certain maximum which is peculiar, to each individual cannot 

 by any artificial means be increased. 



Water, of all foods, seems to have the greatest influence on the 

 composition of milk. When large quantities of water have been drunk, 

 the milk ^contains a higher percentage of water. The amount of 

 albuminoid constituents of the food exerts great influence on both 

 the composition and quantity of the milk. An increase in the pro- 

 teids in the food ' increases the total quantity and solids of the milk, 

 the fats being relatively more increased than the albuminoids. As an 

 illustration of these facts, Weiske has found that a goat which on a 

 diet of one thousand five hundred grammes potatoes and three hundred 

 and seventy-five grammes chopped straw secreted seven hundred and 

 thirty-nine grammes milk, secreted one thousand and fifty-four grammes 

 milk when two hundred and fifty grammes of meat residue was added 

 to the ration, the fat in the milk increasing from 2.71 per cent, to 3.14 

 per cent. In carnivora, also, a rich proteid diet leads to the production 

 of a copious secretion, which may be almost completely arrested by 

 confinement to a carbohydrate diet. In the human female, a rich 

 albuminous diet leads not only to an increase in the amount of milk, 

 but also of its solid constituents, as is seen in the following table: — 



Water. 



Solids. 



Fats. 



Casein. 



Sugar and 

 Extractives. 



On scanty diet, . . . 914.0 

 One week later, after abun- 

 dant meat diet, . . 880.6 



86.0 

 119.4 



8.0 

 34.0 



35.5 

 37.5 



39.5 

 45.4 



