392 THE SUPPORTING TISSUES. 



the liver of dogs which have been poisoned with phosphorus after 

 having previously fasted for twelve days. In such an event it 

 scarcely seems admissible to attempt to account for the presence of 

 the large amounts of fat in the liver on the theory of a transposi- 

 tion. Bauer, moreover, has pointed out that while in such cases a 

 largely increased elimination of nitrogen occurs, there is evidence to 

 show that a non-nitrogenous portion of the albuminous molecule is 

 retained, as the absorption of oxygen and the elimination of carbon 

 dioxide are decreased by one-half. 



A further proof of the possible origin of fats from albumins has 

 been furnished by Hofmann. Experimenting with maggots of 

 flies, he determined the amount of fat in one portion directly, and 

 then permitted a second portion of the same weight to develop in 

 defibrinated blood containing a known amount of fat. These were 

 then killed and analyzed. The result showed that they contained 

 an amount of fat which was from seven to eleven times as large 

 as the total amount of fat in the blood, plus the amount which they 

 originally contained. 



Of the manner in which the fat originates from albuminous 

 material we know nothing definite, but we may assume that non- 

 nitrogenous groups are here first split off, and that the fats are then 

 formed from these synthetically. That an actual liberation of fatty 

 radicles can occur directly appears very unlikely, as we have no 

 evidence whatever to show that the albuminous molecule contains 

 any radicles with more than six or nine atoms of carbon. Of the 

 nature of these non-nitrogenous groups we know nothing. We 

 have shown, however, that most albumins contain a carbohydrate 

 group, and that glucose and glycogen can both be derived from 

 that source. The question hence suggests itself, Is it possible that 

 the formation of fats from albumins takes place with the inter- 

 mediary formation of carbohydrates? As a matter of fact, there 

 is evidence to show that this may occur, as the possible origin of 

 fats from carbohydrates is now well established. This transforma- 

 tion represents one of the most important synthetic phenomena 

 which occur in the animal world, and is of the nature of a synthetic 

 reduction, in which the CHOH groups of the carbohydrates are 

 transformed into CH 2 groups. 



That fats may actually be formed from carbohydrates can be 

 demonstrated in various ways. Two animals from the same litter 

 and approximately of equal weight are starved until the stored fat 

 has mostly disappeared. The one is then killed so as to ascertain 

 the amount of albumins and fats which still remains. The other 

 animal is now fed with a definite quantity of some cereal, the con- 

 tained amounts of albumins, starch, and fat of which arc known. 

 The feces are carefully collected and the amount of non-resorbed 

 fat and albumins ascertained. After a variable period of time this 

 animal is also killed, and the amount of albumins and fat esti- 

 mated. The increase in the amount of albumins must, of course, 



