Cattle Feed and Digestion. 149 



taining the size in the several digestive organs, and effi- 

 ciency in their functions. 



Bulk in food is evidently necessary also to maintain size 

 and natural proportion in the organs, frame-work, and 

 form of the body itself. For instance, the breathing power 

 would be reduced according to any reduction in the size 

 of the lungs; and in the structure of the lungs, the size of 

 the air cells is increased and maintained by the large pro- 

 portion of nitrogen in the air breathed ; the nitrogen 

 serving as diffused and expansive filling, amongst which 

 the oxygen freely circulates, the larger bulk of nitrogen 

 maintaining the full natural size in the cells of the breath- 

 ing organs. 



The same is true of the crude, innutritive portions of the 

 blood, which comprise over half its bulk. If all parts of 

 the blood were naturally nutritive, and used for nutrition, 

 a condition of emptiness in the blood-vessels would follow; 

 but this is neither natural nor necessary. On the contrary, 

 it is both natural and necessary that a large portion of the 

 blood should be innutritive, the innutritive part being me- 

 chanically necessary to keep the blood-vessels — the arteries, 

 particularly — expanded to their ordinary and natural size, 

 as we find them in our farm animals. 



In the body, or its external surface, the breadth or 

 width of the back across the loins and of the hips is usu- 

 ally according to the size of the abdominal region. And 

 how, it may be asked, could size in the millions of cattle 

 mainly subsisting on grass and hay, be maintained other- 

 wise than by the expansive influence of natural bulk in 

 their feed ? 



The truth is, that the frame-work and flesh growth of the 

 animal is formed around the lungs, and the digestive or- 

 gans that comprise the alimentary canal, and that the ex- 

 tent of flesh-growth and size of frame-work is largely de- 

 pendent upon the size of the mold around which they 



