THE JERSEY, ALDERNEY AND GUERNSEY COW. 6 1 



the natural stimulus — the act of sucking — is in full 

 operation. 



Some cows yield enormous quantities, and I am 

 really inclined to regard the very extraordinary drain 

 occasionally occurring by the udder of a poor lean cow 

 as unnatural and unhealthy. It is not unfrequent to 

 see in large dairies an emaciated animal, with every 

 indication of great constitutional weakness, and even 

 the unmistakable signs of phthisis, yet yielding gallons 

 of blue watery milk. We frequently observe secreting 

 organs, from some cause or other, unusually active, 

 much to the injury of the animal's health, and some- 

 times fatal effects result. This is the case in different 

 forms of diabetes, and the persistence of a poor milk 

 secretion to the last moments of an animal's life, months 

 and months after it should naturally have ceased, may 

 really be regarded as an abnormal state. At all events, 

 this view of the subject is w^orthy of consideration. 



Long continuance of mammary secretion may depend 

 on the system adapting itself with difficulty to a great 

 constitutional change. When a cow is in calf, the 

 development of the foetus calls for blood which is drawn 

 from the udder, and the function of the latter ceases. 

 If, on the other hand, a cow that is not pregnant lays 

 on flesh, the deposition of fat necessarily restrains the 

 production of milk. But the transudation of principles 

 from the blood in the mammal becomes in the course 

 of time little more than a mechanical process ; and pro- 

 vided the materials enteringf the blood are not stored 



