FOODS AND DIETETICS. 79 



2. Oleaginous Group. C, O, H. 



Animal fats and oils "j Found in the adipose tissue of ani- 



Stearin, olein f mals, seeds, grains, nuts, fruits 



Palmitin, fat acids j and other vegetable tissues. 



3. Carbohydrate Group. C, O, H. 



Saccharose, or cane-sugar Sugar-cane. 



Dextrose, or glucose 



Levulose, or fruit-sugar 



Lactose, or milk-sugar Milk. 



Maltoes Malt, malt foods. 



Starch Cereals, tuberous roots, and legu- 

 minous plants. 

 Glycogen Liver, muscles. 



4. Inorganic Group. Water; sodium and potassium chlorids; sodium 

 calcium, magnesium, and potassium phosphates; calcium carbonate; and 

 iron. 



5. Vegetable Acid Group. Malic, citric, tartaric, and other acids, found 

 principally in fruits. 



6. Accessory Foods. Tea, coffee, alcohol, cocoa, etc. 



The protein principles of the food, after undergoing digestion and conver- 

 sion into amino acids, are absorbed and transformed into the form of pro- 

 teins characteristic of the blood plasma and the lymph. Of the proteins 

 thus brought into relation with the living protoplasm, a small percentage only 

 is utilized in the repair of its substance. This is known as tissue protein. A 

 large percentage circulating among and permeating the tissues is acted upon 

 by them directly, and reduced to simpler compounds without ever becoming a 

 part of the tissue itself. This is known as circulating protein. In the process 

 of tissue metabolism all the proteins suffer disintegration, and give rise to 

 the production of some carbon-holding compound, probably fat, and some 

 nitrogen-holding compounds which eventually produce urea. The inter- 

 mediate stages are possibly represented by glycin, creatin, uric acid, etc. An 

 excess of proteins in the food is followed by their decomposition, by the pan- 

 creatic juice, into leucin and tyrosin, which, by the agency of the liver, are con- 

 verted into urea. The disintegration of the proteins is attended by the dis- 

 engagement of heat: they thus contribute to the energy of the body. 



The oleaginous principles, after digestion, are absorbed into the blood, 

 from which they rapidly disappear. It is probable that a portion of the fat 

 enters directly into the composition of living protoplasm, out of which it again 

 emerges at some subsequent stage in the form of small drops' which make 



