XI.] COMPOSITION OF FATTENING ANIMALS 209 



contains does also increase, but not so rapidly as the 

 fat, so that its percentage of the total weight actually 

 falls off It should also be noticed that the fat animal 

 contains a smaller proportion of water than the same 

 animal in a store condition, lean meat is a much more 

 watery substance than fat, so that the accumulation of 

 fat tends to reduce the proportion of water in the whole 

 body. If we can assume that the different animals 

 slaughtered in the various stages of fatness fairly 

 represent the kind of changes that the single animal 

 would have gone through while it was being fattened, 

 we can use these figures of Lawes and Gilbert to 

 ascertain the composition of the increase in live weight 

 which the animals put on in passing from the store to 

 the half-fat, and from the half-fat to the fat condition. 

 It will then be found that in the case of oxen which are 

 being steadily fattened from the time they are young, 

 the increase of weight will consist of about one-third 

 water and two-thirds dry substance, about three-fourths 

 of the latter consisting of fat. In the final finishing 

 stage, when the animal is fully grown, about three-fourths 

 of the increase will be dry matter, 90 per cent of which 

 will consist of fat In the case of sheep, there is more 

 mineral matter in the increase because of the amount of 

 alkaline salts in the wool ; but despite the nitrogenous 

 nature of the wool, the live weight increase of sheep is 

 even less nitrogenous and more fatty than that of oxen. 

 In fact, about 75 per cent of the increase of weight in 

 fattening sheep is made up of fat itself. In the case of 

 heavy fat pigs the increase put on is still less nitro- 

 genous and more fatty, there being about 80 per cent of 

 fat and only 7 per cent of nitrogenous matter in the 

 increase. While these figures give us a pretty clear 

 idea of the nature of the changes that are going on 

 when the animal is fattened, they do not tell us how the 



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