Anatomy and Physiology of the Mammary Gland. 99 



due entirely to this cause, and are to be prevented only by 

 attention to the parents, so as to bring their systems into a 

 more healthy state. No cause is more potent in producinii: a 

 retention of colostrum than too generous feeding directly after 

 parturition, on highly nitrogenous and oleaginous substances. 

 We have known whole litters of pigs to be lost from the sows 

 being fed almost exclusively and to excess on barley-meal. The 

 reproduction of colostrum with each deliver}' shows also the im- 

 propriety of " milking round," no time being thus given for 

 this new and important office of the mamma' to be properly 

 performed. 



Fig. 8. 



Microscopical appearance of 

 colostrum. In this tlui(1, in addi- 

 tion to the ordinary milk globules, 

 gramdar corpuscles, varying in size 

 from ^o'jfoth to -g^oth of an inch 

 are present. These corpuscles are 

 marked a, a, in the illustration. 





Srdly, Age. — Although the amount of milk yielded by a heifer, 

 or other young animal, may be considerable, it is not until 

 adultism has been reached that the mammary glands secrete the 

 fullest quantity. At this period all the organs are in their most 

 vigorous condition, and if not overtaxed may remain for several 

 years without showing any marked signs of decay. Both the 

 quantity and quality of the milk of old animals have suffered 

 loss, the latter often more so than the former, and as such, cows 

 of this description ought not to be retained for dairy purposes. 



^thly. Temperament. — This plays an important part in the 

 production of milk. A cow of an irritable or nervous tempera- 

 ment is rarely a good milker. It is the quietly disposed, bland, 

 and mild animal which fills the pail. The influence of the 

 mind over the secretion of milk is very remarkable. This is 

 doubtless best seen in the human subject, but it belongs also to 

 the lower animals. Dr. Carpenter writes that " the formation 

 of this secretion is influenced by the nervous system to a greater 

 degree, perhaps, than tliat of any other. The process may go on 



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