302 ORIGIN OF BODY FAT OUT OF FOOD FAT 



all the characteristics of mutton fat. Rabbits fed on barley have 

 fat like barley oil. Green-food eaters have a hard fat poor in 

 olein, seed-eaters a soft fat. Horses fed on oats have a soft fat, 

 on hay a hard fat. Hard fat is characteristic of fat derived from 

 carbohydrate food. If there is some fat and much carbohydrate in 

 the food the body fat takes on the character of the fat. 



In the formation of carbohydrate into fat a higher compound 

 is built, and energy must therefore be expended, and thus food 

 fat is laid on in preference. 



THE ORIGIN OF BODY FAT OUT OF FOOD FAT 



Hoffmann fasted a dog 30 days till the body had lost 39-5 per 

 cent, of its weight, and was almost fat-free ; then fed it for five 

 days with bacon fat, giving 370-8 grin, fat and 49-4 grm. proteid 

 daily. The dog put on 1353 grm. fat, of which not more than 

 131 grm. could have arisen from the proteid assimilated. 



Henriquez and Hansen fed two pigs for nine months with barley 

 meal to which they added linseed or cocoa-nut oil. Samples of 

 subcutaneous fat were excised from the back at intervals of time, 

 and showed abundant deposit of these oils. 



Munk fasted a dog for 19 days to a loss of 32 per cent, body 

 weight. In the next 14 days he gave altogether 3200 grm. meat 

 and 2850 grm. mutton fatty acids. The body weight increased 

 17 per cent., and he separated from the dog's body no less than 

 1100 grm. fat with scissors and scalpel. This fat melted at 40, 

 while normal dog's fat melts at 20 C. Feeding rape-seed oil to 

 fasted dogs he obtained a fat fluid at body temperature containing 

 17 per cent, more oleic acid than normal, and some erucic acid, 

 which is a constituent of rape-seed oil. Erucic acid was also 

 detected in the chyle in a man with a fistula of the thoracic duct 

 to whom this oil was given. 



QUANTITATIVE RELATIONS OF FEEDING FATS 



When Rubner gave more fat to a previously fasted animal than 

 was sufficient to cover the amount of body fat metabolised during 

 the fast, he found 82 to 92 per cent, of the excess was stored up 

 in the body. Pettenkofer and Voit calculated that 87-86 per cent. 



