FEEDS von ANIMALS 81 



vn\\ weeks witliout food and several days without water. 

 But how long; ran it live without oxygen? Only for a few 

 minutes. It is assumed, however, that the animal will take 

 care of this part of its nourishment itself by means of its power 

 of respiration. But how about the animal that is bred with 

 a small lung capacity or is weak in constitution? Breeding- 

 counts, then, in providing an oxygen supply. 



Animals are sometimes kept in places and under conditions 

 which prevent their getting a normal supply of oxygen. If 

 the ventilation is poor, if too many animals are kept in a given 

 space, if animals pile up so as to prevent proper breathing, if 

 they eat too much and check respiration, if they become 

 l)loated so that the diaphragm presses against the lungs, a 

 lack of oxygen may result, and animals may suffer. 



Exercise. — The most important feature of exercise, in the 

 opinion of the author is in the influence upon respiration. 

 By exercise the organs of respiration are developed and more 

 oxygen is taken in. Thus the value of a pasture, with some 

 animals at least, is more to furnish oxygen than to furnish 

 feed. 



Fire. — Oxygen is as important to the animal body as it is 

 to fire. If a piece of cardboard is laid on top of a smooth 

 topped lamp chimney the light goes out at once. The draft 

 is stopped and no oxygen comes in to support the flame. 

 There can be no fire without oxj^gen. Fire can be kept up in 

 a stove onl}^ as long as there is oxygen passing into the stove 

 and coming into contact with the fuel. A blast furnace de- 

 velops heat enough to melt iron, but this high degree of heat 

 is caused by burning coke, which is almost pure carbon, under 

 forced draft, which gives a large quantity of oxygen. 



Metabolism. — The foregoing illustration serves to show the 

 importance of oxygen in ordinary combustion. It is just as 

 important in metabolism in the animal body. And any 

 lack of development of chest capacity or any environment 

 which hinders the abundant intake of pure air is a serious 

 menace to animals. So, on the other hand, the man who pro- 

 vides his animals by breeding and environment with this power 

 and ability to obtain an abundance of oxygen has a lead over 

 his fellow farmers who pursue a different course. 



