GROWTH. 437 



life, it very frequently, however, assumes an abnormal or patho- 

 logical character at this age. A similar remark refers equally to 

 the fattening of agricultural stock, a process which consists 

 essentially in an augmentation of the fat in the organism, and 

 very often assumes a course very different from that of normal 

 nutrition ; for we cannot regard the development of a fatty liver 

 in geese, or the frequently observed partial disappearance of the 

 nitrogenous constituents of organs, as, for instance, the muscles, 

 in certain modes of fattening, as normal processes. Unfortunately, 

 however, we are not entirely in possession of the conditions neces- 

 sary to give any one special direction to the process of nutrition, 

 by which we might be enabled to determine the relations already 

 indicated. The difficulties which the unequal development of 

 heterogeneous organs oppose to the determination of the metamor- 

 phosis of matter during the period of growth, depend upon the 

 circumstance that we are not able to make nutrition assume any 

 special form, either by means of food or any other external 

 relations. The ingenious combinations of Liebig have sufficiently 

 shown us the conditions under which, independently of proper 

 food, a more abundant deposition of fat may be formed in the 

 animal organism ; and many of .the investigations prosecuted by 

 Boussingault and his pupils have confirmed this by the most 

 striking proofs. Daily experience has further taught us that 

 increased exercise of the organ gives rise to an increase of volume 

 and weight exceeding the normal growth, whilst the deposition of 

 fat is at all events very greatly favoured by the opposite relations. 

 But although we have actually arrived at many general and clear 

 ideas of these relations by means of laborious investigations and 

 ingenious deductions, we cannot boast of being in possession of 

 clear ideas based upon thoroughly exact inquiries. In accordance 

 with the object of the present work, we abstain from all diffuse 

 disquisitions and involved deductions, and limit ourselves to the 

 facts yielded by exact inquiry. 



Boussingault* has instituted some experiments on pigs, with a 

 view of ascertaining the development of the osseous system, and 

 with special reference to the mineral constituents. 



I. A newly born pig weighed 650 grammes; its dried skeleton 

 48'25 grammes; the ash 20*73 grammes. 



II. A pig aged 8 months weighed 60055'0 grammes; its dried 

 skeleton 290 TO grammes; the ash 1349*5 grammes. 



* Ann. de Cliim. et de Phys. 3me S&-. T: 16, p. 486-493. 



