PHYSIOLOGY AT THE FABM. 



PART FIRST. 



THE ORGANS OF NUTRITION IN THE QUADRUPEDS OF 

 THE FARM IN GENERAL. 



IN acts of life there is a continual wear and tear of the 

 whole substance of the animal frame, so that, to preserve the 

 same weight from day to day, there must be a supply of food 

 afforded with only short intervals of interruption. When the 

 frame is in a state of growth that is, when its weight is daily 

 increasing there must be an amount of food sufficient not 

 merely to cover the loss by wear and tear, but also to supply 

 the material for the increase of weight. The food, as a whole, 

 must represent the substance of the living body which it sus- 

 tains. There may be in the food elementary particles which 

 do not enter into the substance of the animal that is fed. 

 These are thrown off as useless along with the particles de- 

 tached in the wear and tear of the body. But within a short 

 period of time, the food taken in must contain all the elemen- 

 tary particles that go to make up the fabric of the animated 

 being and the constitution of its fluids, otherwise the health 

 of the being will not be maintained. There are, at the least, 



