Symptoms. 693 



(mechanical reaction of degeneration), wliicli is freqnently ab- 

 sent if the blow be repeated a number ot tmies, bnt alter a 

 pause reappears. 



Provide.! the intra-nniscular nerves remain intact they respond to mechanical 

 stimulation of the muscle belly with a contraction caused ^y/neir excitability it 

 there is already degeneration of the nerve, especially after destruction ot the cells 

 of the infeiim horns or of the peripheral nerves, their excitability is lost and under 

 these circunsauces the muscle fibers which are extremely excitab e will give only 

 a Jow contraction which is due exclusively to the mechanical stimulation and is 

 produced entirely without nervous influence. 



In cases where the spinal cord exclusively is involved, 

 there is no pain. In exceptional cases, the insensitive area is 

 margined by a hyperesthetic zone, this is due to secondary 

 spinal meningitis. i i ^ 



As a rule, there is no ataxia. One can only conclude from 

 the severe disturbances of locomotion, which are not propor- 

 tional to the paresis, and which increase with the loss ot the 

 power of vision, that there is simultaneous ataxia, provided 

 that there is no great loss of muscular power. 



If the disease involves the sacral portion ot the cord, the 

 urine trickles away, and there is involuntary defecation but it 

 the disease affects higher portions of the cord retention ot 

 urine and feces is observed, copious discharges of urine taking 



place at times. ,, . i i + .^ 



Among the trophic disturbances the simple muscular atio- 

 TDhv which is caused by persistent supranuclear paralysis, must 

 be mentioned. Towards the end of the first week there may be 

 muscular atrophy associated with degeneration reaction m the 

 area involved in' the nuclear paralysis, provided the mliamma- 

 torv changes are extensive (Hutyra & Marek). In some cases 

 there is edema, and now and then, localized sweating is observed 

 The symptoms of inflammation of the various portions ot 

 the spinal cord agree in the main with the symptoms produced 

 by contusion of the same portions (see page 686). It the m- 

 flmnmation extends to the medulla and if the connection between 

 the brain and the respiratory center is not completely inter- 

 rupted, serious symptoms may make their appearance,^ such 

 as difficulty in swallowing, irregularity of the heart, which is 

 sometimes 'accelerated, and sometimes slowed, irregular respi- 

 ration, etc., and finally, death may occur suddenly owing to 

 paralysis of the respiratory center. 



Diffuse myelitis generallv involves a circumscribed portion 

 of the cord and extends rapidly either upwards or downwards 

 (Mvelitis ascendens, M. descendens). In occasional cases, the 

 area originallv involved is large. In the majority of cases it 

 commences in "the more posterior parts of the cord, and withm a 

 short time paralvsis and loss of sensation of the tail, the^ croup, 

 and the hind legs occur, associated with incontinence ot urine, 

 involuntary defecation and relaxation of the sphincter ot the 



