334 RETROGRESSIVE PROCESSES 



of physiologists now support the view advanced in the sentence 

 opening this paragraph. Since proteids contain carbohydrate 

 groups, and since fats can be formed from carbohydrates, the 

 possibility of the formation of fats from the proteids in this 

 indirect way cannot be denied. It is also possible that the 

 nitrogen-containing groups may be split out of the amino-acids 

 of the proteid molecule, and that the non-nitrogenous residues 

 can then be built up into fatty acid molecules as large as the 

 molecules of stearic, palmitic, and oleic acids ; but we have no 

 proof that either of these processes occurs in the normal cell 

 or in the cell that is undergoing degeneration. 



PATHOLOGICAL FAT ACCUMULATION 



For a long time fatty degeneration was looked upon as one 

 of the chief evidences that fat was formed directly from proteid, 

 for the cell protoplasm seemed, morphologically, to be changed 

 directly into fat in this process. Additional support was also 

 claimed from the supposed increase in fat in the ripening of 

 cheese ; from the formation of abundant fat by maggots living 

 in fat-poor blood or fibrin ; and by the apparent conversion of 

 proteids into fatty acids and soaps in the postmortem change, 

 adipocere. But it has now been well established that there is 

 no true conversion of proteid into fat in the fatty degeneration 

 produced experimentally by poisoning with phosphorus, etc., 1 

 and the other supposed instances of fat-formation above cited 

 have been discredited by various methods which it will not serve 

 our purpose to discuss here, beyond mentioning that one of the 

 chief sources of error lies in the fact that many fungi and 

 bacteria 2 can form fat from proteid. 



It having been rendered probable that fat was not formed 

 by disintegration of the proteid of the degenerating cells, it 

 remained to determine what the source of the fat observed in 

 the cells under pathological conditions might be, and this part 

 of the problem has been largely cleared up by Rosenfeld. This 

 investigator proceeded as follows : Animals were starved until 

 they were extremely poor in fat, then fed upon easily identified 

 foreign fats, such as mutton tallow (which has a high melting- 

 point and can combine with little iodin) or linseed oil (which 

 has a low melting-point and can combine with much iodin). 

 The animals under these conditions laid up in their fat depots, 

 including the liver as well as the subcutaneous tissues, large 



1 See Taylor, Jour. Exp. Med., 1899 (4), 399. 



2 See Beebe and Buxton, Amer. Jour, of Physiol., 1905 (12), 466 ; Slosse, 

 Arch. Internal. Physiol., 1904 (1), 348. 



