GROWTH. 441 



fat of the egg is consumed. The remaining results are readily 

 obtained from the above numerical data. 



Schmidt and Bidder have instituted a very admirable observa- 

 tion on a nearly full-grown cat, in reference to the assimilation of 

 muscle and fat. This animal gained 337 grammes in weight in 

 the course of eight days, when fed on flesh containing fat; the 

 question therefore arose, whether the muscular substance only, 

 or the fat, or both together, had contributed to this increase of 

 weight. The animal had consumed during this experiment 

 1866*7 grammes of flesh, with 27*4 grammes of fatty tissue, and 

 had eliminated 62*36 grammes of nitrogen. Now, since, according 

 to Schmidt's analysis, the flesh consists of 70*26 of water, 5*7l 

 of fat, 22'83^ of muscular substance, and 1*2 g- of mineral matters, 

 (the muscular substance, when free from water and salts, contain- 

 ing 53*01 of carbon and 16*11 of nitrogen), we may easily 

 perceive that these 62*36 grammes of nitrogen must have been 

 derived from the decomposition of 387'09 grammes of muscular 

 substance, or of 1695'5 grammes of flesh. As 1866*7 grammes of 

 flesh were consumed, the difference between the two quantities 

 gives us 171'2 grammes as the quantity of flesh retained in the 

 body. As, however, the increased weight of the body amounts to 

 337 grammes, the question arises, how far the remaining portion 

 of the assimilated materials (155*8 grammes) is derived from 

 assimilated fat or from the water retained in the body. These 

 387*09 grammes of decomposed dry muscular substance contain 

 205*20 grammes of carbon ; but in addition to this nitrogen 

 (62*36 grammes), 194*02 grammes of earbon were eliminated, and 

 consequently 18*11 grammes remained in the body. Since, there- 

 fore, the muscular substance is more than sufficient to compensate 

 for the carbon which has been excreted during the metamorphosis 

 of matter, it is not conceivable that the fats, together with 

 the muscular substance, can have participated largely in 

 the oxidation; from hence Schmidt further concluded, and no 

 doubt correctly, that the urea produced by the decomposition of 

 the muscular substance must be separated through the kidneys 

 before the remaining carbon and hydrogen of the muscular sub- 

 stance are exhaled in a state of oxidation through the lungs 

 and skin. As only 1*98 grammes of fat are eliminated with 

 the faeces in the form of saponified lime and magnesia, and as, 

 according to Schmidt's analysis of the fatty tissue, 129*25 grammes 

 of fat are taken up within the eight days, 127*27 grammes of fat 

 are assimilated and remain in the body, in addition to the above 



