VAN PELT'S COW DEMONSTRATION 



bers. Likewise it may be true that it matters little how small 

 the cow is. If the organs vital to constitution are greatly 

 developed in proportion to the other parts of the body she 

 will more likely resist disease than a larger cow weaker pro- 

 portionately in these constitutional parts. 



Large Volume of Air Essential 



Strength of constitution depends primarily upon the 

 amount of pure, fresh air that enters the body and the man- 

 ner in which it is utilized by the lungs in purifying the 

 blood. 



If the nostrils, the trachea or windpipe, and other cham- 

 bers through which the air travels on its way to the lungs 

 are large, open and well distended the volume of air enter- 

 ing the body will be large, and thus far the indications will 

 point to healthfulness. 



Oxygen alone purifies blood, and fresh air is the only 

 medium in which it is conveyed to the blood. Every par- 

 ticle of air that reaches the lungs and comes in contact with 

 the blood passes first through the nostrils and later through 

 the windpipe. If these channels are small, one of two things 

 happens : either a small volume of air enters, or the cow must 

 breathe, more rapidly than the cow with a large nostril. Ob- 

 servation teaches, however, that the respiration of one cow 

 is not perceptibly more rapid than that of another. There- 

 fore, the conclusion may properly be drawn that the cow 

 with the small nostril does not take into her lungs the great 

 amount of air that the cow with the large, open and dilated 

 nostrils and windpipe does. 



Capacity of Thorax 



Quite as important as an indication of vigorous consti- 

 tution are the size and capaciousness of the thorax, or the 

 chamber in which the heart and lungs are located. Small- 

 ness or lack of development in this part of the body pro- 

 hibits greatness of heart and lung development, resulting in 

 limited stamina, vigor and ruggedness. To insure ample 

 room for the fullest growth of the heart and lungs the cow 

 should be extremely deep from the top of the shoulder to the 

 floor of the chest, fairly broad in the chest, deep in the region 

 of the heart girth and well sprung in the fore rib. Cows 

 that are at once narrow and shallow in the chest cavity, tucked 

 up and pinched in the space occupied by the heart are always 

 troublesome and never persistent feeders or producers. 



Although reasonable breadth of chest is to be desired, 

 the mistake is sometimes made in laying too much stress 



T231 



