FAT PRODUCTION 195 



shown for instance that 1000 grams of protein 

 added to a maintenance ration caused 235 grams 

 of fat to be produced in the body. The value of 

 protein for fat production is therefore 235 -f- 250 or 

 94 that of starch. Similarly it was found that the 

 value of fat for fat production compared with the 

 value of starch for fat production was 2-4 in the 

 case of the fat of oil cakes, 2-2 for the fat of cereals, 

 and I '9 for the fat of coarse fodders such as hay or 

 straw. By means of these figures the starch equi- 

 valent for fat production of any food could be 

 calculated. But when the figure calculated in this 

 manner was compared with the figure found by 

 direct experiment on the lines described above for 

 linseed cake, the calculated starch equivalent was 

 almost always found to exceed the starch equiva- 

 lent experimentally determined. Thus in the case 

 of linseed cake the starch equivalent calculated 

 from the digestible nutrients by applying Kellner's 

 relative values for fat production gave the follow- 

 ing result: 



lb. starch 

 equivalent 



27-0 per cent, digestible protein x 0-94 = 25-38 

 9-3 per cent, digestible fat x 2*4 = 22*32 



26-2 per cent, digestible carbohydrate 



+ 4-5 per cent, digestible fibre = 30*70 



100 Ibs. linseed cake = 78-40 



Since 1000 grams of starch had been shown by 

 direct experiment to cause the production of 250 



132 



