428 OF NUTRITION. 



That whilst mere increase in the quantity of food, irrespective of its compo- 

 sition, has no effect in increasing the quantity of nitrogen eliminated by the 

 kidneys, an increase in the proportion of nitrogenous diet is followed by an 

 increased discharge of urea, though this does not rise proportionately for 24 

 hours at least; the effect, however, enduring for some time after the with- 

 drawal of such food. 3. The same holds with regard to uric acid. In fast- 

 ing animals Voit found the proportion of water in the several organs in- 

 creased in amount, so that in a starved cat the percentage of water in the 

 muscles was 76.5 per cent., whilst in a well-nourished cat it only amounted 

 to 74.6 per cent.; and Rauke found that in the muscles of Frogs in winter, 

 when they obtained little or no food, the proportion of water was 83 per 

 cent., whilst in summer, when they were well fed, it was only 79. Such in- 

 crease of the proportion of water has a powerful effect in exhausting the 

 muscles, and probably also leads to depression of the temperature by inter- 

 fering with the processes of oxidation. 



339. The conclusions arrived at by BischofT and Voit upon the effect of 

 feeding their Dog on pure meat-diet are especially interesting. They found 

 that in order that the animal should neither lose nor gain in weight, a daily 

 supply of meat equal to from ^V^h to ^th of the whole weight of its body 

 was required (a much smaller proportion than that found requisite by Bid- 

 der and Schmidt in the experiments on the Cat); and that if less than this 

 were supplied, a loss of weight took place in consequence of the animal con- 

 suming some of its own flesh and fat; whilst if more than this proportion 

 were supplied, a gain in weight occurred. But to produce a daily increase 

 in weight constantly increasing weight a relatively larger proportion of 

 food was continually required, until at last a maximum was attained; the 

 animal then loathed its food, consumed no more, and rapidly returned to its 

 standard weight. At the same time they found that the quantity of meat 

 which the dog required to cover loss on the one hand, and to form flesh on 

 the other, varied always with the mass of the body. In the well-fed animal, 

 therefore, it required more, in the badly fed less, to produce the same effect. 

 They further conclude that when large quantities of meat are consumed, the 

 products of its retrogressive metamorphosis take up or combine with the 

 oxygen of the blood, and that thus the fat of the animal is spared; the ani- 

 mal's temperature being sufficiently maintained by the combustion of the 

 secondary products of the disintegration of the albuminous compounds. 



340. These results have been verified by Ranke in experiments upon him- 

 self, with the exception that he found that he was unable to subsist entirely 

 upon a meat diet, and still less, as Hammond had already shown ( 61) upon 

 pure albumen. Large supplies of meat with diminution of hydrocarbon- 

 aceous compounds invariably diminished the fat of the body. The method 

 of diminishing excessive obesity suggested by Mr. Banting, and which con- 

 sisted in augmenting the use of flesh and reducing the consumption of farina- 

 ceous and oleaginous food to a minimum, is founded, therefore, on strict 

 physiological principles. The economy that is effected by a varied diet, and 

 the immense loss of material that results from restricting man to an exclu- 

 sively animal diet, have already been fully dwelt upon (chap. v). An 

 extraordinary amount of albumen undergoes disintegration on a pure meat 

 diet. Thus Ranke 1 found that whilst a healthy man ordinarily excreted 

 about 570 grains of urea per diem, the amount rose to 1327 grains per diem 

 on a pure flesh diet, and he draws particular attention to the fact that so far 

 from the increased excretion of urea being due to augmented muscular work, 

 the first effect of an excessive meat diet is not that of increased strength, but 



1 Ranke, Grundzugc der Physiologic, 1874, p. 19G. 



