MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. . 261 



dispose of the energy of the alcohol, and from what other source did it get an exactly equal 

 amount to replace i' I 



The conclusions, therefore, are: 



1. The law of the conservation of energy obtained with the alcohol diet as with the ordinary 

 diet. 



2. The potential energy of the alcohol oxidized in the body was transformed completely into 

 kinetic energy, and appeared either as heat, or as muscular work, or both. To this extent, at 

 any rate, it was used like the energy of the protein, fats, and carbohydrates of the food. 



THE PROTECTION OF BODY MATERIAL BY ALCOHOL. 



General considerations. Previous experiments and their explanation. — The belief was for- 

 merly quite general that alcohol has a specific pharmacodynamic action in retarding the metabolism 



of body material, both fat and proteid. As much of the earlier experimenting implied that alcohol 

 in moderate quantities tends to " prevent waste" or ■■conserve the tissues." and its oxidation in 

 the body was not understood, this effect was naturally attributed to its action as a drug. Later, 

 as the functions of the non nitrogenous nutrient- of food came to be better understood, and the 

 fact that alcohol is oxidized as they are in the body became fully established, the view has 

 become common that its effect in retarding or protecting metabolism is to be explained by a 

 nutritive rather than a pharmacodynamic action — that, in other words, it tends, by its own oxida- 

 tion, to prevent the oxidation of other materials. This latter function of alcohol, however, has 

 been denied on two grounds: 



1. The increased circulation of the blood through the peripheral capillaries and the fall of 

 body temperature which follows the ingestion of alcohol have led to the theoretical inference 

 that the energy supplied to the body by the oxidation of the alcohol is lost by the extra radiation 

 or heat it causes, so that it can not do the work of the fats and carbohydrates in protecting 

 food or body material from consumption. This ground, however, is hardly tenable since, as 

 shown beyond, the fall of body temperature with ordinary doses is very small, and the amount 

 of extra heat radiated is only a fraction of that supplied by the alcohol. 



2. The other ground for doubting the power of alcohol to protect body material from con- 

 sumption is that of direct experiment. That it may protect fat is generally conceded, but there 

 are a number of reliable experiments on record in which the replacement of the carbohydrates 

 and fats of a ration by alcohol has been followed by an increased elimination of nitrogen. This 

 has been explained by the assumption that alcohol tends to increase rather than diminish the 

 catabolism of protein in the body. On the other hand there is a considerable amount of exper- 

 imental evidence to the effect that alcohol may and at times does serve as a protector of protein. 



As explained in a review of the experimenting upon this subject'' it seems to us that the 

 conflicting results may be explained by the hypothesis of two opposing tendencies of alcohol, the 

 one pharmacodynamic and the other nutritive. This view makes the former a specific, and some- 

 times, if not always, temporary action of alcohol, by which it increases the catabolism of protein, 

 while the latter action is that resulting from its oxidation. According as the latter or the former 

 action predominates the alcohol may protect protein or fail to do so. In favor of this theory is 

 the fact that it explains and harmonizes the results of previous experimenting and those of our 

 own experiments also. 



In considering the efficiency of alcohol for the protection of body fat and protein it is impor- 

 tant to distinguish between two questions. Does alcohol protect these materials at all '. Is it 

 equal in protecting power to the isodynamic amount of fats or of carbohydrates, or of a mixture 

 of the two? The comparisons in these experiments are between nearly isodynamic amounts of 

 alcohol and the other ingredients. 



"Report of Physiological Subcommittee of Committee of Fifty for the Investigation of the Liquor Problem, 

 Boston, Houghton, .Mifflin & Co. (In press at the time of this writing. ) See also a more detailed review of the sub- 

 ject by Rosemann. Der Einfluss des Alkohols auf den Eiweissstoffwechsel; Arch. f. d. ges. Physiol., Bd. 86, 

 1901. pp. 307-503. 



Vol. s-Nn. 6 3 



