520 NUTRITION. 



cease with the life of the tissues, and of which we are able to recognize only the final 

 results. 



3. Recognizing the products, urea, carbonic acid, and water, as representing probably 

 the evolution of a certain amount of heat, we cannot account for the heat actually pro- 



.duced in the body by the amount represented by the urea and carbonic acid discharged. 

 If we admit that hydrogen is oxidized in the body, resulting in the evolution of heat and 

 the production of water, this will enable us to account for all the heat actually manifested 

 as heat,, leaving an excess which may be converted into force. 



4. Our experiments show pretty clearly that, when no food is taken and when, food 

 being taken, muscular work is performed so that there is loss of body- weight, water is 

 actually produced in the body. This, and this only, enables us to account for all the heat 

 evolved under these conditions. There is no reason to suppose that the processes in- 

 volved in the production of heat are radically changed in their character when enough 

 food and water are taken to maintain a uniform body-weight. 



5. Animal heat is produced mainly by oxidation of the nitrogen, carbon, and hydrogen 

 of the tissues, the waste of these elements being supplied by food. Probably the oxida- 

 tion of carbon and hydrogen is a more important factor in calorification than the oxida- 

 tion of nitrogen ; at least it is certain that the heat- value of the oxidation of carbon and 

 hydrogen is greater than that of the oxidation of nitrogen, and the quantity of heat thus 

 produced is much larger. Of the two elements, carbon and hydrogen, the oxidation 

 of which produces animal heat, the heat-value of the hydrogen is by far the greater. 



6. It is probable that there is always a certain amount of oxidation of hydrogen in the 

 body, and that this is necessary to maintain the animal temperature ; and it is almost cer- 

 tain that this occurs during prolonged abstinence from food and when the production of 

 heat is much increased by violent and protracted muscular exertion. It may be, also, 

 that there is an active and unusual oxidation of hydrogen as well as of carbon in fevers. 



Alcohol, which is so extensively used as a measure of sustaining treatment in fevers, 

 is now almost universally recognized as an element consumed in the body and not dis- 

 charged to any considerable extent as alcohol. According to Brande, Cognac brandy 

 contains 46 per cent, of absolute alcohol. With a specific gravity of 0-930, one ounce of 

 brandy weighs 406-875 grains and contains 187'1625 grains of alcohol. The alcohol, with 

 a composition of C^eOa, contains 12 -9 per cent, of hydrogen, or 24-14 grains, and 52*65 

 per cent, of carbon, or 98'54 grains. . The heat-value of 24*14 grains of hydrogen equals 

 214*77 heat-units. The heat-value of 98-54 grains of carbon equals 182-44 heat-units. 

 Taking, then, the total heat-value of the hydrogen and carbon contained in one ounce of 

 brandy, it amounts to 397-21 heat-units. If we assume that a man produces four heat- 

 units per pound weight of the body per hour, the amount of heat normally produced in 

 twenty-four hours by a man weighing 140 pounds is equal to 13,440 heat-units. The 

 quantity of brandy required to supply this amount of heat, according to the calculations 

 just made, would be a little less than thirty-four ounces. Theoretically, then, it is easy 

 to see how alcohol may furnish material to supply heat and save waste of tissue in fevers ; 

 and it is not very unusual, in certain stages of fever, to administer from sixteen to 

 thirty-two ounces of brandy in twenty-four hours. 1 



"We conclude this subject with the following query, which has occurred to mind in 

 connection with reflections upon the question of the oxidation of hydrogen as one of the 

 sources of animal heat : 



If the excessive heat produced in essential fevers be due in part to an excessive oxi- 

 dation of hydrogen, why would not the exhaustion and rapid emaciation which attend 

 the progress of fever be more or less moderated by supplying hydrogen to the system 

 in the form of fatty matters, starchy matters, sugar and alcohol, until the fever has 



1 For a more complete account of the experiments given above, the reader is referred to an article by the author, 

 entitled Experiments and Reflections upon Animal Heat. American Journal of the Medical Sciences, Phila- 

 delphia, April, 1879, p. 338, et seq. 



