398 NUTRITION. 



of development of organic muscular fibres, which could be 

 said only just to exist in them before, or were present in a 

 very imperfectly developed condition. 



Respecting the mode and conditions of the process of 

 growth, it need only be said, that its mode seems to differ 

 only in degree from that of common maintenance of a part ; 

 more particles are removed from, and many more added to 

 a growing tissue, than to one which only maintains itself. 

 But so far as can be ascertained, the mode of removal, the 

 disposition of the removed parts, and the insertion of the 

 new particles, are as in simple maintenance. 



The conditions also of growth are the same as those of 

 common nutrition, and are equally or more necessary to its 

 occurrence. When they are very favourable or in excess, 

 growth may occur in the place of common nutrition. Thus 

 hair may grow profusely in the neighbourhood of old 

 ulcers, in consequence, apparently, of the excessive supply 

 of blood to the hair-bulbs and pulps ; bones may increase 

 in length when disease brings much blood to them ; and, 

 cocks' spurs transplanted from their legs into their combs 

 grow to an unnatural length ; the conditions common to all 

 these cases being both an increased supply of blood, and 

 the capability, on the part of the growing tissue, of avail- 

 ing itself of the opportunity of increased absorption and 

 nutrition thus afforded to it. In the absence of the last- 

 named condition, increased supply of blood will not lead 

 to increased nutrition. 



