FATTY TISSUE. 559 



shown, also free, non-volatile fatty acids, although in very small 

 amounts. 



Human fat is relatively rich in olein, the quantity in the subcutaneous 

 fatty tissue being 70-80 per cent or more. 1 In new-born infants it is 

 poorer in oleic acid than in adults (KNOPFELMACHER, SIEGERT, JAECKLE) ; 

 the quantity of olein increases until the end of the first year, when it is 

 about the same as in adults. The composition of the fat in man as well 

 as in different individuals of the same species of animals is rather variable, 

 a fact which is probably dependent upon the food. According to the 

 researches of HENRIQUES and HANSEN the fat of the subcutaneous fatty 

 tissue is richer in olein than that of the internal organs; this has also been 

 observed by LEICK and WiNKLER. 2 In animals with a thick subcutaneous 

 fat deposit the outer layers, according to HENRIQUES and HANSEN, are 

 richer in olein than the inner layers. The fat of cold-blooded animals 

 is especially rich in olein, The fat of domestic animals has, according 

 to AMTHOR and ZINK, a less oily consistency and a lower iodine and 

 acetyl equivalent than the corresponding fat of wild animals. Under 

 pathological conditions the fat may have a markedly pronounced varia- 

 tion. The fat of lipoma seems, from JAECKLE 's experience, to be poorer 

 in lecithin than other fats. 



The fat stored up in the organs and tissues can be changed somewhat 

 by the composition of the fat of the food, still, according to ABDERHALDEN 

 and BRAHM, S the fat actually occurring in the cells (with the exception 

 of the real fat cells) is not dependent in its composition upon the kind 

 of food fat taken. 



The properties of fats in general, and the three most important varieties 

 of fat in particular, have been considered in a previous chapter, hence 

 the formation of the adipose tissue is of chief interest at this time. 



The formation of fat in the organism may occur in various ways. The 

 fat of the animal body may consist partly of fat absorbed from the food 

 and deposited in the tissues, and partly of fat formed in the organism 

 from other bodies, such as proteins (?) or carbohydrates. 



That the fat from the food which is absorbed in the intestinal canal 

 may be retained by the tissues has been shown in several ways. RAD- 

 ZIEJEWSKI, LEBEDEFF, and MUNK have fed dogs with various fats, such 

 as linseed-oil, mutton-tallow, and rape-seed-oil, and have afterward 



J See Jaeckle, Zeitschr. f. physiol. Chem., 36 (literature). 



2 Knopfelmacher, Jahrbuch f. Kinderheilkunde (N. F.), 45 (older literature); 

 Siegert, Hofmeister's Beitrage, 1; Jaeckle, Zeitschr. f. physiol. Chem., 36 (literature); 

 Henriques and Hansen, Skand. Arch. f. Physiol., 11; Leick and Winkler, Arch. f. Path, 

 u. Pharm., 48. 



3 Zeitschr. f. physiol. Chem., 65. 



