THE UDDER. 5 



total storage capacity of about 3 cubic decimetres; and for one milk- 

 cistern, on an average, '25 cubic decimetre. 



It is unnecessary, for the purposes of this book, to enter into a detailed 

 description of the distribution of the muscles, ligaments, adipose tissue, 

 nerves, blood and lymph vessels, and of the skin and hair of the udder. 



Fig. 11. Plaster of Paris Cast of the Milk-cistern and Milk-ducts of the posterior half of 

 the Milk-gland of a Dutch Cow. Natural size. (Fiirstenberg.) 



Four milk-glands are often spoken of, as if there were two on each side 

 of the udder, an assumption warranted neither by the course of the milk- 

 ducts leading to the two milk-cisterns, situated on the same side, nor by 

 any other anatomical structure. 



The physiological action which gives rise to the secretion of milk in 

 the udder has, as its chief centre, the above described gland-lobules, which 

 are covered inside with an epithelial cell-layer, and outside with a net-work 



