RURAL VETERINARY SECRETS 63 



terns and the alveoli. When the teats are worked with the hands 

 or milking cups, the nerves surrounding them are irritated, and 

 through them the secreting glands are stimulated, causing their con- 

 traction and the discharge of their contents. 



The veins along the belly leave the front of the udder and go 

 forward in a more or less winding manner, branch more or less often, 

 and eventually disappear through holes on the abdominal floor, 

 termed milk-wells, then pass along on the inside of the upper side 

 of the breast bone, to be eventually united to the internal thoracic 

 vein (the mammary vein of the human). 



MAMMARY VEIN 



Ihc mammary vein then will be accepted as affording some in- 

 dication at least of the milking capabilities of a cow. Some breed- 

 ers' associations call for certain arrangements of those veins, as fol- 

 lows : Single and double extension, single and double branches, 

 single and double chest extension, or umbilical (navel) veins). The 

 wells vary in number from one to three on each side of the animal, 

 licncc tlicy should be of good size. 



Tlic greater the capacity of the arteries and veins connected 

 with the udder, the larger the milk secretion zvill usually he. Theory 

 and practice then seem to unite and back up the ideals of the dairy- 

 man, one of which is a great development of the mammary veins. 

 The arterial supply cannot be seen, and only parts of the venous 

 system of the udder are visible, viz., the abdominal veins and those 

 underlying the skin of the udder, yet reasonable conclusions can be 

 drawn from the development of the milk veins. 



HOLDING UP THE MILK 



Various theories have been advanced to account for this illus- 

 tration of animal perversity and human peculiarity; the latter prob- 

 abl}^ had been shown in the form of abuse, and of course, stamps 

 the exhibitor as one not fit to own or milk cows. Wing, in "Milk 

 and Its Products," states that the holding of the milk is due to the 

 l^resence of sphincter muscles at the branching of the ducts, and 

 that this muscular tissue is connected with the abdominal muscles, 

 which is contracted as a result of fright, dislikes, etc., will cause 

 the milk to be retained in the udder, or, as it is termed, the cow 

 holds up her milk. So far we have been unable, either by dissection 

 of udders or consultation of authorities on the anatomy and histo- 



