128 TEXT-BOOK OF PHYSIOLOGY 



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 consumed by the above- 

 mentioned factors. The diet scale of Vierordt, for example, yields the 

 following : 



120 grams of protein yields 494 .88 Calories. 



90 grams of fat yields 841 .77 Calories. 



330 grams of starch yields 1358 .28 Calories. 



2694.93 Calories 



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 combined 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 continues 

 until about 40 per cent, of the weight has been lost, when death generally 

 ensues. This results from the fact that the active tissue cells consume, 

 for the purpose of maintaining 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 condition are 

 as follows: hunger, intense thirst, gastric and intestinal uneasiness and 

 pain, diminished pulse-rate and respiration, muscular weakness and emacia- 

 tion, a lessening in the amount of urine and its constituents, diminished 

 expiration of carbon dioxid, an exhalation of a fetid odor from the body, 

 vertigo, stupor, delirium, at times convulsions, a sudden fall in body tem- 

 perature, and finally death. The duration of life after complete depriva- 

 tion of food varies from eight to thirteen days or more, though this period 

 can be prolonged if the animal be supplied with water, this being more 

 essential under the circumstances than the organic materials which can be 

 supplied by the organism itself. The duration of the starvation period 

 will naturally vary in accordance with the previous condition of the animal 

 and the amount of reserve food, especially fat, the body contains. 



The extent and the character of the metabolism that the body undergoes 

 in starvation can be determined from an examination of the excretions. 

 Thus the excretion of nitrogen declines very rapidly during the first few days 

 a fact which has been attributed to the consumption of the surplus protein 

 food. The amount of nitrogen eliminated and hence the protein metabo- 

 lized depend, mainly on the amount of protein consumed daily before the 

 starvation period was inaugurated. At the end of four or five days when 

 the surplus protein has been metabolized and the tissues begin to metabo- 

 lize their own protein, the excretion remains fairly constant, from about 13 

 to 10 grams daily, until toward the close of the starvation period, when the 

 amount eliminated falls very rapidly. In several instances of prolonged 

 fasting by human beings the nitrogen elimination fell as low as 4 to 3.5 

 grams daily, indicating a protein metabolism only of from 25 to 18.75 grams. 

 As proteins contain about 16 per cent, of nitrogen, i part of nitrogen equals 



