666 PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



degeneration of various organs, the increase in urea elimination proving 

 that the fat was derived from the albumen. 



As regards the carbohydrates, which may also be regarded as a 

 possible source of fat, considerable doubt exists as to the manner in 

 which the}' act. As is well known, carbohydrates are always an 

 important, constituent of fattening foods, and it may be assumed either 

 that the carbohydrates, being themselves readily oxidized, save the 

 non-nitrogenous bodies derived from the proteids, and so enable them to 

 be converted into fat, or that they may be directly concerned in the 

 formation of fats. It is clear that carbohydrates may undergo the 

 butyric acid fermentation, and other ferment actions might likewise 

 serve to manufacture other fats. Thus, Pasteur claims that glycerin, 

 which is the basis of neutral fats, may be formed from pure carbo- 

 hydrates. It is probable, therefore, that in both of these ways the 

 carbohydrates serve to increase the adipose tissue of the body both 

 directl}- and by enabling the non-nitrogenous matters derived from the 

 proteids to be converted into fat and stored up as such. 



The following experiments recently made in Vienna with a hog 

 thirteen months old and weighing one hundred and forty kilos are of 

 special interest in this connection : Two kilos of soft-boiled rice were 

 given daily as fodder, and a comparison of the income and outgo 

 demonstrated the daily deposit in the tissues of thirtj'-eight grammes of 

 albumen and 351.8 grammes of fat. For the development of the latter 

 at most only 65.4 grammes of proteid in the food, corresponding to 33.6 

 grammes fat and 7.9 grammes fodder fat can be reckoned on. The 

 excess (351.8 — 41.5 = 310.3 grammes), or 88.2 per cent, of the entire 

 amount of fat deposited in the body, can only have been derived from 

 the carbohydrates of the food. 



So, also, in the case of geese and bees, the development of fat from 

 carbohydrates admits of proof. The dog, however, like other carnivora. 

 seems incapable of developing fat from carbohydrates. 



III. THE PATE OP THE CAKBOHYDKATE FOOD-CONSTITUENTS. 



The metamorphosis of the carbohydrate food-constituents may be 

 somewhat more readily followed. It has been seen that under the influence 

 of the salivary, pancreatic, and intestinal ferments, starch and dextrin 

 are turned into maltose and cane-sugar into invert-sugar, the sugar as 

 such entering the blood by absorption ; or, in a rich amylaceous diet, 

 splitting up in the intestine into lactic and butyric acids. In the blood, 

 the sugar is either reconverted to a member of the starch group 

 (glycogen) in a process to be considered directly, or is rapidly oxidized 

 into C0 2 and H 2 0, the intermediary products being, however, unknown. 

 That sugar is directly oxidized would seem probable from the fact that 



