24 HUMAN PHYSIOLOGY. 



The method of determining the proper amounts of both kinds of food is 

 as follows : 



1000 grains of bread (2 oz.) contain 300 grs. C. and 10 grs. N. 



To obtain the requisite amount of nitrogen from bread, 30,000 grains, 

 or about 4 Ibs., containing 9000 grains of carbon and 300 of nitrogen, 

 would have to be consumed. Under such a diet there would be a large 

 excess of carbon, which would be undesirable. On a meat diet the reverse 

 obtains : 



1000 grains of meat (2 oz.) contain 100 grs. C. and 30 grs. N. 



To obtain the requisite amounts of carbon from meat, 45,000 grains, or 

 about 6*4 Ibs., containing 4500 grains of carbon and 1350 grains of nitro- 

 gen, would have to be consumed. Under such circumstances there would 

 arise an excess of nitrogen in the system, which would be equally undesir- 

 able and injurious. By combining these two articles, however, in proper 

 proportion, the requisite amounts of carbon and nitrogen can be obtained 

 without any excess of either, e. g. : 



2 Ibs. of bread contain 4630 grs. C. and 154 grs. N. 

 #" meat " 463 " 154 " " 



5093 C. 308 N. 



The amount of carbon and nitrogen necessary to compensate for the loss 

 to the system daily would be contained in the above amount of food. As 

 about 3^ oz. of oil or butter are consumed daily, the quantity of bread can 

 be reduced to 19 oz. In the quantities of bread and meat above mentioned, 

 there are 4.2 oz. albumin, 9.3 sugar and starch. 



DIGESTION. 



Digestion is a physical and chemical process, by which the food intro- 

 duced into the alimentary canal is liquefied and its nutritive principles 

 transformed by the digestive fluids into new substances capable of being 

 absorbed into the blood. 



The Digestive Apparatus consists of the alimentary canal and its 

 appendages, viz. : teeth, salivary, gastric and intestinal glands, liver and 

 pancreas. 



Digestion maybe divided into seven stages: prehension, mastication, 

 insalivatioa, deglutition, gastric and intestinal digestion and defecation. 



