422 



NUTRITION. 



0-3796 of alb. of the silica which was taken in the ood, 0'0464 of 

 a Ib. did not re-appear in the excretions ; their application to 

 the formation of the epidermis and hair seems, however, to be 

 proved by the amount of silica which was shown to be present 

 in these parts by Brunner and Valentin as well as by Gorup- 

 Besanez. 



Boussingault * made a series of experiments with a view of 

 settling the question whether nitrogen was or was not exhaled 

 through the lungs. These experiments, which were made on turtle- 

 doves fed upon millet, gave the following result for the distribution, 

 through the excrements and the perspiration, of the elements taken 

 with the food. We have calculated the mean of the results of two 

 observations, the one of which extended over five, and the other 

 over seven days. 



Sacct made a perfectly similar series of experiments on fowls which 

 had been fed on barley, at the same time that they had swallowed 

 chalk and sand. These animals (a cock and a hen) had increased 

 19'18 grammes in weight during the seven days of the experiment; 

 this increase depended upon the assimilation of 12*436 grammes 

 of organic matter and 6*744 grammes of mineral substances ; if these 

 are abstracted from the food, we find from Sacc's experiments, that 

 the elements are distributed as follows in the faeces and the 

 perspiration : 



* Ann. de Chira. et de Phys. 3 Se'r. T. 1 1, p. 433. 

 t Ann. d. Ch. u. Pharm. Bd. 52, S . 77. 



