254 
NEUROTOMY. 
substance acquires a firmer texture ; the number of bloodvessels 
in it in the course of time diminish — it shrinks in substance as in 
cicatrization, and the separated extremities of the divided nerve 
approach nearer and nearer each other. But Swan found it diffi- 
cult to determine at what period this intervening new material 
was capable of carrying on the nervous function. 
If we examine the nerves of the limbs of fiorses any length of 
time after they have been operated on in the usual manner, we 
find oblong bulbous swellings occupying the intervals from which 
portions of nerve have been excised ; and these tumours we 
observe to be larger above than below, measuring three or four 
times the bulk of the original nervous chords. This consequent 
enlargement it is which makes it so objectionable to perform 
neurotomy on the side of the fetlock, where the horse, should he 
be disposed to hit his legs, would be certain almost to strike the 
bulbous nerves, and when he had done so, for the moment render 
himself dead lame from the exquisite pain the blow occasioned 
him. Between this nervous tumour and the cellular tissue by 
which it is surrounded, firm and dense adhesions exist every 
where ; so that it requires some dissection with a sharp knife to 
raise the tumour out of its bed. Cut into, its substance is found 
to be pearl-white, solid, and firm, more like cartilage, in fact, than 
nervous substance. 
Of the Regeneration of Nervous Matter our chief 
knowledge is with respect to the regeneration of the tubular 
fibres. “ Many years ago, our countryman, Doctor Haighton, 
in making experiments to determine the function of the vagus 
nerve, shewed, that when a nerve is simply divided, without 
taking away any portion of it, union would take place, and the 
nerve resume its proper office. If a considerable piece were 
excised, so as to leave much interval between the cut ends, there 
would be union after the lapse of some time, but not by true 
nervous fibrous, 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 
