DAIRYING 



49 



Gland -lobules, e, Outlet tube, 

 (x 00.) (Furstenberg.) 



Alveoli, d, Common duct, (x 800.) 

 (Furstenberg.) 



PLATE 8 The Milk Glands. 



these alveloi become swelled as shown in i, but at other times are 

 flat and contracted as in 2. During secretion the milk flows from 

 these alveoli in the gland lobules through fine ducts or tubes that 

 increase in size as they near the milk cistern which is a cavity 

 holding about one-half a pint located just above the roots of the 

 teat. From this milk cistern the milk flows through the tube in 

 its center to the end of the teat when the sphincter muscle closes 

 the opening. The cow has no control over this muscle and but 

 little control of another muscle at the root of the tent which helps 

 to hold the milk that accumulates in the cistern. The muscles 

 surrounding the gland near the body of the animal are partially 

 under control and this enables the cow to "hold up" her milk 

 under nervous excitement. 



The control which .a cow has over her milk secretions is 

 similar to that "which a man has over the salivary and the tear 

 glands. Certain conditions cause one's "mouth to water" or the 

 saliva to flow and one's "eyes may water" either voluntarily or in- 

 voluntarily. In the same way the act of milking causes the milk 



