442 NUTRITION. 



I7l*2 grammes of flesh and the 138'4 grammes of water. After 

 the subjection of this calculation to the corrections required in 

 consequence of various causes, and especially of the partial oxidation 

 of the sulphur Schmidt reckoned that 40*16 grammes of mus- 

 cular substance and connective tissue, 143*42 grammes of fat, 

 1*78 grammes of salts with sulphur, and 134*15 grammes of water, 

 were assimilated in eight days by this animal, weighing 2177 

 grammes, and that in the case referred to the cat, for every kilo- 

 gramme, daily assimilated 18*346 grammes of muscular substance 

 and fat. 



However indispensible such conclusions and the calculations 

 based upon them may be for the purpose of obtaining a deeper 

 insight into the metamorphosis of animal matter, we ought not to 

 disguise the fact, that they only lead us to a very slight degree of 

 relative certainty. Independently of the circumstance that slight 

 deviations in the observation often lead to very different results, 

 or justify very different conclusions, we must be conscious that in 

 our inability to determine all these causes with exactness, or to 

 represent them in an arithmetical form, we very often employ for 

 our equations certain postulates, several of which may in the 

 existing circumstances be equally probable, although they essen- 

 tially modify our calculations. We must therefore here be 

 cautious in dealing with illusive equations, w r hich, although per- 

 fectly correct in an arithmetical point of view, may lead us into 

 the most flagrant errors. 



By feeding cats alternately with flesh and pure fat, Schmidt 

 has moreover given probability to the view, that the albuminates 

 are always more readily decomposed in the body than the fats, 

 and that a diet consisting exclusively of fat (or of an insufficient 

 amount of albuminates with an abundance of fat) causes the nitro- 

 genous matters of the body to be subjected to metamorphosis, 

 whilst the fats, which are taken up are, on the contrary, at first 

 either entirely or for the most part deposited in the body, being 

 oxidised at a later period, and probably only by degrees. 



It is from this and a previously indicated point of view, that 

 we must consider the results of those numerous experiments 

 which have been instituted in reference to relations of nutrition 

 during the fattening of animals generally, or of cows with a view 

 of obtaining a more abundant supply of milk. In association with 

 Schmidt's experiment, we have to notice an observation made by 

 Persoz,* who fattened geese on maize ; the blood of the geese 

 * Compt. rend. T. 18, pp. 245-254. 



