Chap, iv.] PROPERTIES OF NERVOUS FIBRES. 401 



essence of the nervous fibre ; since even nervous fragments trans- 

 planted and grafted under the skin of dogs waste and are 

 regenerated, as they would be after a simple section. 



How many things are still unexplained in this singular nervous 

 restoration ! How can we comprehend the influence of the 

 motory and sensitive cells upon the fibres ? Why, some days 

 after the section of the motory nerve, does the motricity of the 

 nerve disappear, since the axile filament, which is the essential 

 part of the fibre, apparently preserves its integrity ? It is 

 generally admitted that the genesis of nervous fibres is only 

 possible in the embryon; it would necessitate, it is said, very 

 complex blastemas, which the simple process of nutrition is 

 powerless to produce. Nevertheless, in cases of nervous restora- 

 tion, after resection, there is generation of nervous fibres. 

 Finally, the nervous medulfary substance, or myeline, is a 

 ternary, hydrocaibonised body ; now, in the case of nervous 

 regeneration, it is necessarily secreted, either by the Schwann's 

 sheath, or by the axile cord. Here then is a fresh case 

 of synthesis of a carbonised ternary matter in an animal 

 tissue. 



D D 



