CHAP. XII. 



VALUE OF FAT OR OIL IN FOODS. 



207 



and woody fibre, but so that the first set got a large and the second a 

 small quantity of fatty matters. So general is the distribution of fat, 

 that some difficulty was experienced in finding substances sufficiently 

 free from it to produce a proper contrast ; and it was only by the use of 

 malt-dust on the one hand, and of rape-cake mixed with oil on the 

 other, that it was possible to obtain the requisite difference. The 

 feeding was divided into three periods, and the nature and quality of 

 the food given will be best understood from the table on page 206. 



" These quantities were so arranged as to give as nearly as possible 

 the same amount of nutritive matters to each series, except that the 

 first got about twice as much oil as the second. This is more distinctly 

 seen in the following table, calculated from the analyses of the different 

 foods, and giving the exact amount of each nutritive ingredient con- 

 sumed per head : 



" Without entering into the details of the weighings at each successive 

 period, which were made with great minuteness, it may suffice to give 

 the subjoined abstract of the results : 



" Looking at these results, it seems impossible to doubt that the 

 larger gain which appears throughout the whole of the first series must 

 be due to the excess of fatty matters supplied in the food. And this 

 is very strikingly seen in the last period, when exactly the same 

 quantities of the same substances were given to each series, except that 

 the first received 84 Ib. of oil more than the second, and the conclusion 

 is irresistible that the surplus gain of 85 Ib. must have been produced 

 by it. Neither can it be doubted that the 259 Ib. by which the first 

 series exceeds the second diking the second period is caused by the 

 additional 113 Ib. of fat contained in the food. 



