242 NATURE AND LIFE. 



and fixed consistency of the surfaces, sheaths, or moulds, 

 in which the cells of the new bones are to deposit and 

 grow together. The method of cutting out assures the ex- 

 istence of such a firm and unchanging mould by keeping a 

 sheath of bone in the best conditions to procure a new 

 growth of bony tissue, while that of sub-periosteal resec- 

 tions expects the regeneration of the organ out of a perios- 

 teum unsupported, injured, weakened, and bent under the 

 influence of muscular contraction. Sedillot, who has the 

 finest feeling for ancient medical art, and understands it 

 thoroughly, has not left us in ignorance that Celsus had al- 

 ready, a little less than a thousand years ago, proposed cut- 

 ting out of the bones ; but the teaching of Celsus had not 

 been accepted in practice. The famous French surgeon 

 rescued these precepts from oblivion, proved their useful- 

 ness and importance by new arguments, explained the 

 causes that warrant them, and their success, and has thus 

 restored to the skillful and enlightened practice of the art 

 one of the most precious means of relief for the formidable 

 injuries and diseases of the bones. 



II. 



Life is a searching and expanding force which strives 

 to seize upon all that comes within the range of its activity. 

 We have just seen that it fills up the voids produced by 

 the removal of certain organic parts ; we are now about to 

 see that it wins, by inverse operation, certain parts which it 

 adds to living beings ; for grafts are nothing less than liv- 

 ing fragments pieced on to an organism already complete. 

 In the vegetable graft, the grafted part does not make an 

 integral portion of the single whole to which it has been 

 transplanted. It does not live with the same life. It de- 

 velops itself after a kind of parasitic fashion at the expense 

 of the other, like misletoe on the oak ; and, whether the 

 grafted fragment be or be not of the same species as the 



