534 VI. OCCURRENCE OF LIPIDS IN THE ANIMAL 



(g) Miscellaneous Fatty Acids. Winternitz 88 demonstrated, more than 

 fifty years ago, that iodized fats can be deposited in fat storage depots. 

 Artom and Peretti 89 reported that fatty livers resulted after the feeding of 

 iodized natural fats. Zummo 90 obtained a similar response with brominated 

 ethyl oleate, while Artom and Swanson 91 reported comparable results with 

 several brominated esters. It has also been found that erucic acid, 13,14- 

 docosenoic acid, is incorporated in the adipose tissue of the dog when rape- 

 seed oil is fed in large proportion to the previously fasted dog. 4 Garton, 

 Hilditch, and Meara 8 showed that the characteristic unsaturated fatty 

 acids of whale oil are laid down in the fat depots when a diet rich in whale 

 oil is fed to pigs. They observed that the whale oil glycerides were de- 

 posited principally in the outer back fat, and also, to the extent of 26%, 

 in the perinephric fat. When the diet included 50% of the whale oil, it 

 appeared that the glycerides of this fat had been absorbed and deposited 

 in the body fat without any chemical alteration. 



Arachidic acid, CH 3 (CH 2 )i8COOH, which is not a normal component 

 of animal fats, has been reported by Ellis and Isbell 92 in hog fat obtained 

 from animals which had previously been fed on large amounts of peanuts. 

 This fatty acid obviously had its origin in the peanut oil fed, since this oil 

 contains a high percentage of the acid. On the other hand, arachidonic 

 acid, a tetraenoic C 2 o acid, is found only in animal tissues; thus it must be 

 synthesized there. However, it is probable that the dienoic or trienoic 

 acids serve as building stones for this compound. 44 



d. The "Soft Pork Problem" in Relation to the Ingestion of Unsaturated 

 Fats. Considerable interest has been evinced as to the laws which govern 

 the laying down of adipose tissue, because of the widespread occurrence of 

 the so-called "soft pork." For some time during the twenties, a consider- 

 able proportion of hogs which were slaughtered contained a fat graded as 

 "oily" or "soft," as contrasted with the usual grade classed as "hard." 

 In some carcasses, the fat exhibited such a lack of firmness that the prod- 

 ucts presented a typical soft, flaccid, shapeless condition; this rendered 

 them inconvenient to handle, as well as unattractive to customers. In 

 extreme cases, the meat cuts were practically unsalable. The whole 

 problem has been one of great economic importance. An understanding of 

 the causes of this phenomenon has been obtained from the research of 



88 H. Winternitz, Z. physiol. Chem., 24, 425-448 (1898). 



89 C. Artom and G. Peretti, Arch, intern, physiol, 36, 351-370 (1933). 



90 C. Zummo, Arch. sci. biol. (Italy), 24, 162-168 (1938). 



91 C. Artom and M. Swanson, Federation Proc, 1, 99 (1942). 



92 N. R. Ellis and H. S. Isbell, /. Biol. Chem., 69, 219-238, 239-248 (1926). 



