EVOLUTION OF HEAT. 543 



tion in pure oxygen ; and thus almost every molecular change in the body, 

 but pre-eminently those which are concerned in the disintegration, of its tex- 

 tures, and in the elimination of their products by Respiration, participate in 

 the function of Calorification. The experiments of Ranke, 1 made upon him- 

 self, furnish perhaps the best data on which the absolute amount of heat 

 developed in the body can be calculated ; and they are by so much the more 

 to be depended upon, as the results agree well with the determinations of 

 Frankland on the amount of heat developed by various kinds of aliment 

 during the act of combustion. It may be remarked that the age of Ranke 

 was twenty-four, his height about six feet, and his weight 154 Ibs. The first 

 experiment was made to determine the amount of heat developed on mixed 

 food. The ingesta and. the egesta were equal in amount, the weight of the 

 body remaining the same. The numbers represent grammes : 



Exp. I. Production of heat on the first day of total abstinence from food 

 (commencing 23 hours after the last meal), the iugesta (i. e., consumption of 

 the body itself) calculated from the egesta : 



Ingesta, in Grammes. 

 54.45 Albumen. 

 195.94 Fat. 



Egesta. 

 18.3 Urea. 

 0.24 Uric Acid. 



From these data it may be calculated that the daily production of heat 

 amounted to 2012.8 calories. 



Exp. II. Production of heat on meat diet, the deposition of flesh in the 

 body, and the consumption of fat being calculated from the excretions: 



Ingesta. Egesta. 



1832 grm. of Meat, of which only 1300 grm. 



underwent disintegration. 86 Urea. 

 70 grin. Fat of Food, \ 1 , 1 95 Uric Acid. 



75.14 Fat of Body, ) 1 99 Fieces. 



The daily production of heat produced here was 2799.5 calories. 



Exp. III. Production of heat on non-nitrogenous diet, consumption of al- 

 bumen and deposit of fat in the body calculated from the excreta: 



Ingesta, in Grammes. Egesta. 



51.55 Body Albumen. 17.1 Urea. 



150.00 Fat,"of which 81.5 were deposited. 0.54 Uric Acid. 



So that only 68.5 were burnt off. 90.0 Fieces. 

 300 Starch. 

 100 Sugar. 



The daily production of heat was here 2059.5 calories. With mixed diet 

 the daily production was about 2200 calories. 



Thus during Fasting, . . 2012 Calories were produced per diem. 



On Non-Nitrogenous Diet, . 2059 " " " 



On Mixed Diet, . . . 2200 " " " 



On Abundant Meat Diet, . 2779 " " " 



According to Senator, 2 a dog weighing about 12 Ibs., fed on a pound of meat 

 per diem, gave off, 16-26 hours after food, 12-14 calories per hour, during 

 which time it excreted from 52 to 57 grains of carbonic acid gas. After 

 fasting for 48 hours, it gave off 11.6 calories, and eliminated 51.7 grains of 

 CO 2 , whilst two hours after digestion it gave off 21 calories, and eliminated 

 79.8 grains of CO 2 . 



The average of Rauke's experiments on himself gave the number of calo- 

 ries produced per diem at 2200, which is a quantity sufficient to raise 44 



1 Grundzuge der Physiologie, 1874, p. 566. 2 Centralblatt, 1871, p. 738. 



