534 INDUCTION. 



origin, very frequently excites a similar affection in the other 

 eye, which may he cured hy section of the intervening nerve : 



Loss of sight sometimes produced hy neuralgia ; and has 

 heen known to be at once cured hy the extirpation (for in- 

 stance) of a carious tooth : 



Even cataract has heen produced in a healthy eye hy 

 cataract in the other eye, or hy neuralgia, or by a wound of 

 the frontal nerve : 



The well-known phenomenon of a sudden stoppage of the 

 heart's action, and consequent death, produced by irritation 

 of some of the nervous extremities : e.g., by drinking very 

 cold water ; or by a blow on the abdomen, or other sudden 

 excitation of the abdominal sympathetic nerve ; though this 

 nerve may be irritated to any extent without stopping the 

 heart's action, if a section be made of the communicating 

 nerves : 



The extraordinary effects produced on the internal organs 

 by an extensive burn on the surface of the body ; consisting 

 in violent inflammation of the tissues of the abdomen, chest, 

 or head : which, when death ensues from this kind of injury, 

 is one of the most frequent causes of it : 



Paralysis and anaesthesia of one part of the body from 

 neuralgia in another part ; and muscular atrophy from neu- 

 ralgia, even when there is no paralysis : 



Tetanus produced by the lesion of a nerve ; Dr. Brown- 

 Sequard thinks it highly probable that hydrophobia is a phe- 

 nomenon of a similar nature : 



Morbid changes in the nutrition of the brain and spinal 

 cord, manifesting themselves by epilepsy, chorea, hysteria, and 

 other diseases, occasioned by lesion of some of the nervous 

 extremities in remote places, as by worms, calculi, tumours, 

 carious bones, and in some cases even by very slight irrita- 

 tions of the skin. 



4. From the foregoing and similar instances, we may 

 see the importance, when a law of nature previously unknown 

 has been brought to light, or when new light has been thrown 

 upon a known law by experiment, of examining all cases 



