NEUROTOMY. 219 



and that this was, that the extremities of the divided nerve, par- 

 ticularlv the superior one, became thicker and more vascular : 

 coagulable lymph, having the appearance of albumen, being poured 

 out, and in a short space of time permeated by bloodvessels. 

 Then, both ends of the effused lymph form an union, and anasto- 

 mosing vessels shoot through it. Gradually, this intermediate 

 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 Schwann 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 horses 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 nerve, 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 agfo, 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 



