18 LIVE-STOCK JUDGING 



once then passed back to the mouth from the paunch. 

 It is eventually swallowed to undergo digestion and assimi- 

 lation in the regular way, and to be replaced in the mouth, 

 repeatedly, by other portions until the entire contents of 

 the paunch have been disposed of in this way. The pig 

 is unlike either the horse (Fig. 8) or the ruminating cattle 

 and sheep, which are strictly herbivorous, it being omniv- 

 orous, eating both vegetable and animal matter. It is 

 also monogastric, having but one stomach like the horse, 

 although it has much less capacity of large intestine, and 

 is therefore much less capable of digesting a bulky ration 

 than the horse. 



22. Circulation. The blood stream serves as a transit 

 system, through which the digested nutrient material is 

 conveyed to the tissues and organs to be used for their 

 repair and upbuilding in growth; to be stored up as a 

 reserve fund of energy, as in the case of accumulated fat ; 

 to furnish the essentials for glandular secretion, as in the 

 case of the udder ; or to be utilized immediately, as energy, 

 in the maintenance of body temperature or functional 

 activity in the performance of work. Digestion com- 

 pleted, it remains for the circulatory system to accomplish 

 the assimilation and distribution of the digested food 

 constituents. 



The circulatory system consists of the heart, which 

 serves as a pump ; arteries, which carry the blood, after 

 having been aerated in the lungs and returned to the left 

 side of the heart, to the tissues ; and the veins, which return 

 the vitiated blood to the right side of the heart and from 

 thence to the lungs, where the waste products, collected 

 from the tissues, are discharged as carbon dioxide and its 

 red cells are reloaded with a fresh supply of oxygen. In 

 addition to the blood the lymph is circulated through the 



