438 



NUTRITION. 



III. A pig aged 11| months weighed 67240*0 grammes; its 

 dried skeleton 340/*0 grammes; the ash 1686*0 grammes. 



The ash of these three skeletons, when burned perfectly white, 

 contained : 



According to this result, the pig aged 8 months, which was 

 kept on ordinary food, gained on an average daily 11*7 grammes 

 in the weight of the osseous system, 5*5 grammes of ash, 

 2*4 grammes of phosphoric acid, and 2*8 grammes of lime. The 

 other pig, which lived 93 days longer, and was fed on potatoes 

 only during that time, gained daily 6 grammes in the weight of 

 the dry skeleton, 2*6 grammes of ash, about 1*4 grammes of 

 phosphoric acid, and about 1*6 grammes of lime. 



In the 544 kilogrammes of potatoes which the pig consumed 

 during the last period of 93 days, there were 5440 grammes of 

 mineral substances, including 615 grammes of phosphoric acid 

 and 98 grammes of lime, whilst its skeleton had taken up during 

 the same period of time 129 grammes of phosphoric acid and 

 150 grammes of lime. Consequently, 52 grammes more of lime 

 were taken up than were contained in the potato ash. Besides 

 this, there were 216 grammes of lime discharged with the excre- 

 ments ; consequently, 170 grammes of lime must have been sup- 

 plied to the animal from some other source. Boussingault shows 

 that this lime must be derived from the water in which the 

 potatoes had been boiled. 



We are entirely deficient in investigations instituted in a 

 similar manner in relation to the development of other tissues or 

 organs, when compared with the amount of food. But it would 

 scarcely be out of place were we, before we enter upon the con- 

 sideration of the increase in muscle and fat, to notice the experi- 

 ments of Prevost and Morin, which connect themselves with the 

 observations made by Baudrimont and St. Ange (see p. 369) on 

 the respiration of the incubated egg. The results of these labours 

 may be thus set down : 



