302 THE ROTHAMSTED EXPERIMENTS. 



leave no doubt of very considerable formation of fat from 

 the carbohydrates. 

 Basis of All these re-calculations are in the first place based on the 

 £SnT" assumption, since generally adopted by others, that 100 nitro- 

 genous substance can at the most yield 51.4 of fat, instead of 

 nearly 62, which would be the figure according to the original 

 plan of calculation adopted in the construction of Table 70. 

 Different Then, each experiment is now calculated three ways : — first, 

 *&?"" on tne assumption that the whole of the fatty matter and 

 nitrogenous substance of the food were digested ; secondly, 

 supposing that only 90 per cent, and thirdly that only 80 

 per cent was digestible and available. Lastly, in the case 

 of experiments 4 and 5, after very carefully considering the 

 weights and character of the animals, and the duration of the 

 fattening period, the initial and final composition have been 

 taken, not as in Table 70, the same as in experiment 1, but 

 the initial at a composition three-eighths in advance from 

 the store to the fat condition, and the final composition at a 

 quarter in advance of fatness, compared with the fat pig of 

 experiment 1. It is worthy of remark, that this carefully 

 re -considered independent mode of estimate gives almost 

 precisely the same percentage of nitrogenous substance, and 

 precisely the same of fat, in the increase, in experiment 4, as 

 in the former estimate — namely, now 5.4 instead of 5.3 per 

 cent of nitrogenous substance, and in both cases 79 per cent 

 of fat, the animals being all very fat. Again, the new mode 

 of calculation gives for experiment 5, 6.4 per cent of nitro- 

 genous substance, and 72.3 per cent of fat in the increase, in- 

 stead of 6.5 and 71.2 per cent as formerly adopted. 

 Results Let us first refer to the results of experiment 1, in which 



{lifrngmmis P ara Uel animals were analysed, but in which, as has been 

 food. pointed out, the food was much more highly nitrogenous than 



is appropriate in the fattening food of the pig. Those given 

 in column 1, in which it is assumed that the whole, both of 

 the nitrogenous substance and of the fat of the food, was 

 digestible and available, show that, when we now reckon only 

 51.4 instead of about 62 parts of fat to be derivable from 100 

 nitrogenous substance, even this experiment indicates that 

 the fat in the food, and that derivable from the nitrogenous 

 substance consumed, were scarcely sufficient to cover the 

 whole of the fat of the increase. Obviously, too, if it be as- 

 sumed, according to the more recent estimate, that only about 

 42 parts of fat can be derived from 100 of albuminoid sub- 

 stance, there would then, even in this experiment, with such 

 abnormally high nitrogenous food, be a considerable forma- 

 tion of fat from carbohydrates. 



Turning to the results in the second column, which are 



