ix.j CONSTITUTIONAL STRENGTH. 83 



because we get a larger quantity of fat formed from a 

 given quantity of food. 



173. It is necessary now to look at the other side 

 of the picture. Such animals are delicate, and require 

 more care and protection than others. We have 

 given these animals small lungs, and sluggish livers, 

 and consequently the power of the animal to maintain 

 its warmth is reduced. If such animals are exposed 

 to cold weather, we soon find that they have reduced 

 powers for maintaining their warmth, the healthy 

 condition of the body suffers, and the animal becomes 

 subject to disease. The conditions which render 

 animals energetic, active, and hardy, have in these 

 cases been modified to make them good producers 

 of fat, and in proportion as we have succeeded in this 

 attempt, so we have produced a weak and delicate 

 constitution. 



174. These circumstances fully account for what 

 is known as a loss of constitutional strength. 

 If you seek for this, you find it where the laws of 

 animal life exercise their full influence. The wild, 

 un domesticated animal, possesses a healthy and vigo- 

 rous system, and every part of his body possesses a 

 thoroughly healthy character, and thus the full energy 

 of constitutional strength is maintained. Nature rebels 

 against our " improvements " in the several breeds of 

 stock, and just in proportion as we are successful in 

 producing unnatural specimens, so we find the laws 

 of animal life corning in to check us in keeping up 

 the succession. 



175. Shelter and economy of food, should never be 

 carried out at a sacrifice of the proper ventilation 

 of buildings. It has been shown that animals draw 

 into the lungs atmospheric air, use a portion of the 

 oxygen, and throw off carbonic acid. This carbonic 

 acid is a very dangerous gas, for no animal can live 

 in it, and it should therefore be carried off from the 

 building. An instance showing the deadly character of 



