CHAPTER V. 



PEOBXJCTION" OF MILK 

 ^ 1. The MiLK-GiiANDs and TiamiE Functions. 



Milk is not simply a Secretion, — In order to an nn* 

 derstancling of the influence of tlxe fodder npon tlie 

 quantity and qnalitj of the milk, it is important to gam 

 a clear conception of the mode of formation of the 

 latter. 



The milk is not simply secreted from the Mood, like the 

 nrine in the kidneys or the digesti^^e juices in the stomach 

 and intestines, but is formed in the milk-glands from the 

 cells of the gland itself; it is the liquefied organ. This is 

 shown ^"ven by the composition of its ash, which, like tliat 

 of all tissues, contains much potash and phosphate of lime, 

 while the fluids of the animal body ai^ poor in these sub- 

 stances and rich in chloiide of sodium ; the ash of milk 

 contains three to five times as much potash as soda, while 

 the ash of blood, on the other hand, contains three to five 

 times as much soda as potash. "Were the milk simply a 

 transudate from the blood, it would have a similar compo- 

 sition, and could not serve as the exclusive food of the 

 young animal, since it would not contain all the elements 

 necessary for growth ; but since it is a liquefied organ, it 

 is exactly adapted to build up other organs. 



Structure of the Milk-Glands. — The milk-gland is 

 composed of numherlebs small vesicles, like those repre- 



