ESSAYS 



325 



for further production. The improvement in the quality of pastures effected by 

 phosphatic manures is probably attributable to increased digestibility, and conse- 

 quent higher productive index of the produce. 



In a recent paper ' the author gave reasons for the conclusion that 60 per cent. 



Fig. 2. 



was about the largest amount of body fat an ox could put on. It now appears 

 that, if the productive index of the rations had been lower, the limit attainable 

 would have been less. On the other hand, pigs, which can subsist normally on 

 rations composed entirely of foods which have a very high productive index— e.g., 



1 Jour. Agric. Sa\, vol. ix, No. 2. 



