NERVES. 46 :> 



nerve to affection of the ganglionic portion and of the facial, and 

 by considering the facial as exclusively controlling all motions 



those distributed to numerous muscles of the body when the irritation from 

 dyspnoea is extreme. The pneumono-gastric and the rest of the set associated 

 with it at their roots appear to maintain the sympathy between the heart and 

 the rest of the system. I reply that he allows the ganglionic nerves to 

 be as widely distributed ; and so indeed must be the nerves of sensation, for 

 any vascular part of the body may show sensibility when inflamed. 



2. He argues that the nerves of sensation cannot convey sympathy, because 

 this may occur independently of sensation and some sympathising parts have no 

 sensibility. But all vascular parts may acquire sensibility under inflammation , 

 and therefore all vascular parts must have nerves of sensation. Yet sympathy may 

 doubtless occur without sensation, just as the various nutritive functions occur 

 without it. Still, if the ganglionic nerves are allowed by him to administer 

 to these, they may administer to sympathy. Indeed, sympathy is often the result 

 of sensation only. We do not sneeze unless the sensation in the nose arises to a 

 certain height, not the sensation of smell, but of touch ; and I may remark that 

 Dr. Fletcher appears wrong in arguing that sensation in the nose does not occur 

 before sneezing, because it is not the sensation of smell. Some sympathies 



-are sensations and therefore carried on in some measure at least by nerves of 

 sensation ; other sympathies certainly can have nothing to do with nerves of sens- 

 ation, but it does not follow that they must be carried on by the so called 

 respiratory nerves. 



3. The occurrence of sympathy during sleep he considers an argument that 

 sympathy is independent of the brain. No one can doubt that many sympathies 

 are independent of it. Communications of nerves exist independently of the 

 brain : and Dr. Fletcher is correct in condemning the old hypothesis that the 

 brain is necessary to sympathy. Still this does not show that the so called 

 respiratory nerves must be the sole organs of sympathy. 



4. He maintains that the manifestation of the effects of sympathy, passion, 

 and instinct, are in proportion to the development of this system. Certainly, 

 in proportion to the voluntary muscles, which act under instinct and passion, are 

 the nerves which serve these voluntary muscles. Fish, he urges, have, of the 

 respiratory nerves, only the pathetic and the pneumono-gastric, which latter is 

 in part a nerve of motion like the pathetic, and they have it of great size. Fish 

 display the effects of many instincts and passions. Reptiles have, in addition, 

 the glosso-pharyngeal and facial. Similar additions of other nerves are found in 

 other classes. The glosso-pharyngeal, however, is now proved to be a nerve of 

 special sense, and the facial supplies the voluntary muscles of the jaws and 

 fauces, which in fish were supplied by the pneumono-gastric. But I can see 

 here no argument for these voluntary nerves being exclusive agents of sympathy, 

 although they are used as excitants of voluntary muscles under instinct and 

 passion, and in morbid involuntary excitement of these muscles as well as in 

 volition. 



5. The structure of the sensiferous and ganglionic nerves is similar; and of 



I I 



