220 NEUROTOMY. 



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, Steinreich, and Nasse are the most interesting, 

 that true nervous fibres may be developed in this uniting sub- 

 stance, 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 demonstra- 

 tion of the presence of proper nerve-tubes by microscopical exa- 

 mination. 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." — Todd and Bowman s Physiological 

 Anatomy. 



Return of Sensation. — So far as restoration of function in a 

 nerve can be considered as proof of union of its divided ends, the 

 notable experiment, so impressively set forth by our late Professor 

 Coleman in his " Lectures," concerning the division of the par 

 vagum in horses, is conclusive. If the nerves on both sides of the 

 neck be divided at the same time, or within a short interval of one 

 another, death becomes consecutive on the division of the last; 

 whereas, if an interval of three weeks be allowed between the 

 operations, the animal survives. 



Neurotomy, as performed for lameness, proves the same thing in 

 the case of excision of the substance of the nerve ; the difference 

 being, that, while after simple division the nerve takes but a month 

 or two to have its union and function restored, after excision the 

 time required for regeneration and restoration of function becomes 

 lengthened in some sort of ratio to the quantity of nerve excised. 

 Meyer, who instituted some experiments to illustrate this, found 

 that when he excised one line in breadth of nerve, the reproduc- 

 tion occupied three weeks ; and when two lines' breadth were cut 

 out, two months. Mr. Sewell found, in cases of entire section of 

 the nerves of the limbs of horses, that sensation returned in about 

 a couple of months ; but that when a portion of nerve was ex- 



