I42 TEXT-BOOK OF PHYSIOLOGY. 



proteid escapes in the feces, the heat value of which must also be 

 determined and deducted. This having been done, the physiologic 

 heat value becomes 4.124 calories. 



The following estimates give approximately the number oi kil< 

 gram calories produced when the food is burned to carbon dioxid, 

 water, and urea in the body: 



i gram proteid yields, 4-124 calories 



x fat " 9-353 



i " carbohydrate yields 4-no 



The total number of kilogram calories or kilogram degrees of 

 heat yielded by any of the previously given diet scales can be readily 

 determined by multiplying the quantities of food principles con- 

 sumed by the above-mentioned factors. The diet scale of Vierordt, 

 for example, yields the following: 



120 grams of proteid yields, 494.88 calories. 



9 o " fat " 841.77 



330 " starch - 1358-28 



2694.93 



The total calories obtained from other diet scales would be as 

 follows: Ranke, 2335; Voit, 3387; Moleschott, 2984; Atwater, 3331; 

 Hultgren, 3436. 



Starvation. The relation of the different food principles to the 

 general nutritive process becomes more apparent from an examination 

 of the excretions from the body during the process of starvation com- 

 bined with an examination of the organs and tissues after death. 

 If an animal be deprived entirely of food, a decline in body- weight 

 at once sets in, which continue^until about 40 per cent, of the weight 

 has been lost, when death generally (Jhsues.// 1'liis results from the 

 fact that the active tissue cells consume, for tne purpose of maintain- 

 ing the normal temperature of the body, not only their own reserve 

 food material, but that of the less active or storage tissues as well; 

 and, in consequence, there is a progressive diminution in weight. 



The phenomena which characterize this non-physiologic con- 

 dition are as follows: hunger, intense thirst, gastric and intestinal 

 uneasiness and pain, diminished pulse-rate and respiration, muscular 

 weakness and emaciation, a lessening in the amount of urine and its 

 constituents, diminished exhalation of carbon dioxid, an exhalation 

 of a fetid odor from the body, vertigo, stupor, delirium, at times con- 

 vulsions, a sudden fall in body-temperature, and finally death. The 

 duration of life after complete deprivation of food varies from eight to 

 thirteen Hays or more, though this period can be prolonged ifiSe ani- 

 mal be supplied'with water, this being more essential under the cir- 

 cumstances than the organic materials which can be supplied by the 

 organism itself. The duration of the starvation period will vary in 

 accordance with the previous condition of the animal and the amount 



