HISTORY OF DIFFERENT FOODSTUFFS IN BODY 1047 



the metabolism of the fats, cannot be decided at this time. It is evident 

 that this organ may absorb a considerable proportion of its fat directly 

 from the portal blood. Thus, Raper^ has shown that as much as 30 

 per cent, of cocoanut introduced in the intestine, may be recovered 

 from the liver. The same is true of unsaturated oils, such as cod-liver 

 oil and other fish oils. This probably accounts for their greater nutri- 

 tive value. In addition, it has been shown that the liver possesses 

 the power of desaturating fat, which may render it more easily reduci- 

 ble than saturated fatty acid. But, inasmuch as this organ also aids in 

 synthetizing fatty acid radicles into the complex molecule of lecithin, 

 it is entirely probable that this desaturation constitutes a preliminary 

 step in this process of building up lecithin. While this substance is 

 made up of gylcerin, fatty acids, glyceryl-phosphoric acid, and a nitrog- 

 enous base cholin, it also seems to contain admixtures of proteins or 

 carbohydrates. 



Fatty Degeneration. Obesity. — Under abnormal conditions, the 

 cells of such organs as the liver, heart, and kidneys may undergo 

 degenerative changes which make them appear as if filled with ex- 

 tremely fine globules of fat. This is a common result of poisoning with 

 phosphorus, arsenic or antimony. Although formerly believed to be 

 due to a conversion of the proteins of the cytoplasm into a fat-like 

 substance, fatty degeneration is now known to be caused either by 

 an infiltration of the cells with fat transported from elsewhere or by a 

 transformation of the molecular fat of the cells into a different variety 

 of it. For this reason, it cannot be said that a fatty degenerated cell 

 contains a greater amount of fat than it did normally; in fact, in 

 many instances the reverse relationship holds true. Lusk, however, has 

 shown that these poisons also interfere with the metabolism of the 

 proteins in an indirect way by favoring the conversion of the carbohy- 

 drate-like radicle of the proteins into leucine and tyrosine, necessitat- 

 ing for this reason an increased consumption of protein. 



Obesity signifies a disproportion between the total mass of the 

 body and that made up of fat. This condition is caused by an exces- 

 sive deposition of fat within the different depots of the body, giving 

 rise to changes in the contours of the latter and various interferences 

 with its normal activities and movements. In many instances, 

 however, it is difficult to say just where the abnormal begins, because 

 animals differ very greatly in their fat-carrying capacity. It is 

 evident that the great majority of animals may be made to lay on 

 fat by lessening their expenditure of energy or by increasing their 

 intake of carbohydrates and fats. Since this is a perfectly physiolog- 

 ical phenomenon, the only condition to explain is the excessive deposi- 

 tion of fat on a normal or reduced diet in the presence of a normal or 

 even increased expenditure of energy. It has previously been pointed 

 out that the metabolism of the fats may be dependent in some measure 

 upon the secretion of some ductless gland. In the absence of this in- 

 1 Jour. Biol. Chem., xiv, 1913, 117. 



