372 Bdkeau of Fakmeks' Institutes. 



which line the ultimate recesses or follicles in which the milk 

 ducts ori^'inate. Each of the smallest milk ducts terminates in a 

 cluster of slight dilatations or closed sacks lined by round cells 

 which accomplish the work of selection from the blood and trans- 

 formation of the materials which go to form the milk. Beneath 

 this surface pavement of cells, is a delicate membrane, and be- 

 neath that the network of capillary vessels in which the blood 

 circulates. In health, therefore, none of the blood can get into 

 the milk ducts, except such as has been passed upon by the secret- 

 ing cells and modified as may be necessary, to form the liquid 

 known as milk. The constituents of milk are in the main, water, 

 salts, albumen, casein, fat and sugar, and of these the water, 

 salts and albumen are the only ones that exist ready formed in 

 the blood. The elements that give to the milk its commercial 

 value — the casein, the butter fat, and the sugar — are made up in 

 the udder, by the functional activity of the gland cells. 



Is the color of milk changed from red to white before it reaches the 

 udder? 



Dr. Law. — No; the milk as such does not exist before it 

 reaches the udder. Healthy milk is never red, and it only becomes 

 so by reason of some unnatural condition such as: 



a. The escape of red blood globules or of blood coloring matter 

 through the walls of the gland follicles or milk ducts. This may 

 occur from wounds, bruises, conjection or inflammation of these 

 parts, or from diseased conditions of the blood in which the color- 

 ing matter is set free. 



h. The feeding upon red coloring matter such as madder, which 

 escapes with the milk into the udder follicles and milk ducts. 



c. The presence in the udder and milk ducts of a pigmenit-form- 

 ing microbe, like the micrococcus prodigiosa, which produce a red 

 color in its growths. 



Is there a visible connection between the milk veins and the udder? 



Dr. Law. — The term milk veins, usually applied to the super- 

 ficial abdominal veins, has misled a good many people and led 

 them t^ suppose ihsii those vessels convey milk to the udder, and 



