355 



food was determined. On the average of the cases it amounted to 

 less than ^th as much as was estimated to be stored up in the in- 

 crease of the animals. There was obviously therefore a formation 

 of fat in the body, from some other constituent or constituents of the 

 food. Supposing the fths or more of the stored-up fat which must 

 have been formed in the body to have been produced from starch, 

 it was estimated that it would require 2^ parts of starch to contri- 

 bute 1 part of produced fat. Accordingly, it would appear that a 

 much larger proportion of the consumed dry matter is, as it were, 

 directly engaged in the production of the dry fatty increase, than is 

 represented by the amount of the dry increase itself. 



Thus, taking the average of the cases in which the fatty matter 

 in the food of the pigs was determined, it was estimated that 17*4 

 parts of dry increase were produced for 100 of dry matter of food 

 consumed. Of the 17'4 parts of dry increase, 16-04 are reckoned 

 as fat. But there were only 3*96 parts of ready-formed fatty matter 

 supplied in the food. At least 12-08 parts of fat must therefore 

 have been produced from other substances. If from starch, it would 

 require (at the rate of 2^ parts of starch to 1 of fat) 30' 2 parts of 

 that substance for the formation of 12*08 parts of the produced 

 fat. The ready-formed fat and the starch, together, thus supposed 

 to contribute to the 16'04 parts of fat in the increase, would amount 

 to 34' 16 parts out of the 100 of dry matter of food consumed. But 

 there were, further, 1'36 part of nitrogenous and mineral matters 

 stored up in the increase. In all, therefore, 35*52 parts out of the 

 100 of gross dry matter consumed, contributed, in this compara- 

 tively direct manner, to the production of the 17*4 parts of gross 

 dry increase. 



According to the illustration just given, it appears that there was 

 pretty exactly twice as much of the dry substance of the food, in- 

 volved in the direct production of the increase, as there was of dry 

 increase itself; hence instead of their being, as before estimated, 82 

 to 83 parts of the consumed dry matter expired, perspired, or 

 voided, without as it were being directly involved in the production 

 of the increase, it is to be inferred that, in the sense implied, only 

 about 65 parts were so expired, perspired, or voided. 



It having been thus found that by far the larger proportion of 

 the solid increase of the so-called fattening animals is really fat 



