MILK SECRETION. 23 



on the right side, and two on the left side. The divisions 

 between the two glands on the side are not entirely complete. 

 That is, there is enough connection between the two glands 

 on the same side to allow a portion of the milk to be drawn 

 from the rear teat to the front teat on the same side, and from 



GLAND-LOBULE 

 ALVEOLI 



FIG. 2. Schematic figure showing cross-section of cow's udder; and also 

 enlargement of epithelial cells in alveoli when cow is giving milk (1). Each 

 alveolus is surrounded with a membrane called tunica propria. Cell 

 nuclei not shown. When cow is in milk they are also enlarged. When 

 not the epitheliarcells are flat and the nuclei small and spindle shaped (2). 



the front teat to the rear teat. The milk-glands proper are 

 located near the abdomen and extend downwards into the 

 udder a trifle. The remainder of the udder is filled with ducts, 

 fibrous and connective tissue, muscle, nerves, and blood-vessels, 

 the whole udder assuming a sort of spongy and open condition. 



