CH^P. VIII.] REGENERATION OF NERVOUS MATTER. 229 



interval between the cut ends, there would be union after the lapse 

 of some time, but not by true nervous fibres, nor in such a way as 

 to restore the action of the nerve. It appears, however, from 

 recent observations, of which those of Schwann, Steinruch, and 

 Nasse are the most interesting, that true nerve-fibres may be deve- 

 loped in this uniting substance, but apparently in smaller numbers 

 than in the nerve itself. The proof of the regeneration of the true 

 nerve-fibres depends upon the restoration of the nerve's function, 

 and the demonstration of the presence of proper nerve-tubes by 

 microscopical examination. Perfect restoration of the action of the 

 nerve does not generally take place, owing, most probably, to the 

 fact that the central and peripheral portions of the same fibres do 

 not always meet again. The central portion of a motor fibre might 

 unite with the peripheral segment of a sensitive one, and thus the 

 action of each would be neutralized. 



Nothing satisfactory is known respecting the regeneration of the 

 nervous matter of the brain or spinal cord after a loss of substance 

 from injury or disease. When a portion of the brain is removed in 

 animals, its place is supplied by new matter; but, whether this 

 becomes true cerebral substance, future research with good micro- 

 scopes must determine. 



We refer, on the subjects of this chapter, to the various works on General 

 Anatomy quoted in former chapters, especially to that of Henle ; to Miiller's, 

 and Wagner's Physiology ; to the articles Nerve, and Nervous Centres, in the 

 Cyclop. Anat. and Phys. ; to the fourth vol. of Soemmering's Anat. by Valentin 

 (German and French) ; to Valentin, iiber den Verlauf und die letzten Enden 

 der Nerven; and to Bidder and Volkniann, Die Selbstandigkeit des sym- 

 pathetischen Nervensystem. Leipzig, 1842. The researches of Bidder and 

 Volkmann on the sympathetic system are of great interest, if further obser- 

 vation shall confirm them. These authors describe the peculiar fibres of the 

 sympathetic as originating independently of the spinal cord or brain. Their 

 description of these fibres does not exactly accord with what we have seen of 

 the gelatinous fibres, nor are we at present prepared to express any decided 

 opinion respecting the accuracy of their observations, which are very favour- 

 able to the theory of the independence of the sympathetic system, 



