132 VETERINARY SURGICAL OPERATIONS 



lowed by any trace of dissolution. The unnerving of healthy 

 parts never causes them to break down. Whole regions may 

 be accidentally or experimentally unnerved with impunity and 

 without any subsequent degeneration or disintegration of any 

 part of the unnerved structures. In the case of divided mo- 

 tor nerves the muscles supplied by them will rapidly undergo 

 simple atrophy from disuse but no degenerative changes are 

 ever observed. Disease, deformity, and weakness are the 

 essential pre-requisites to breaking down conditions follow- 

 ing neurotomy. The removal of the nerve supply has only 

 the indirect influence of leaving the diseased parts exposed 

 to increased strain. The interrupted nerve supply is not di- 

 rectly causative. The lesions never exhibit any evidence of 

 progressive degenerations to which the appellation "trophic 

 disturbance" could be appropriately applied. 



2. Return of the Lameness. — The return of the lameness 

 following neurotomy occurs at variable times after the opera- 

 tion. Sometimes the first two or three days of work will 

 bring back a lameness more marked than the previous one, 

 and at other times two years may elapse before there is a re- 

 currence. The cause of increased lameness or its early re- 

 turn is spreading of the inflammation from the initial seat 

 under the influence of the added strain or concussion to which 

 the inflamed area is subjected. Sometimes this new inflam- 

 mation will persist and leave the patient permanently lame; 

 and at other times it will subside and leave the subject perma- 

 nently relieved of the lameness. Lameness occurring a few 

 days after the nerved horse is returned to work is not always 

 serious nor an indication of failure. Longer rest, return to 

 pasture, etc., very often turns into success what at first ap- 

 pears to be a hopeless failure. The return of lameness from 

 every point of view is a spreading of the inflammation and 

 not a restoration of the nerve supply. Nerve supply once in- 

 terrupted by removing a section of a nerve trunk is destroyed 

 forever. It can not be re-established by reunion of the cut 

 ends of the ' trunk, because nerve regeneration is not so 

 effected. (See regeneration, Vol. II.) 



3. Unsightly and Painful Cicatrices.— The incisions into 

 the skin and underlying structures often leave indelible blem- 

 ishes in the form of prominent unsightly scars, which are not 

 infrequently permeated with highly sensitive nervous ele- 

 ments. Aside from their unsightly appearance these scars 

 are harmless unless sensitive, in which case they are capable 

 of causing a very acute and lasting lameness. They are 

 caused by the error of allowing exuberant granulation to 



