TOUCH. 



1183 



usually referrible, in the first place, to the 

 influence of cold and damp ; and it is especi- 

 ally liable to occur in persons of a rheumatic 

 or gouty diathesis. That even the sedative 

 influence of cold may be propagated along 

 the nerve-trunks, and that its anaesthetic 

 effect is not due to its peripheral influence 

 alone, appears from the circumstance remarked 

 by Dr. Graves (loc. cit.), that the paralysis 

 induced by handling snow, or by immersing 

 the hands in freezing mixtures for some little 

 time, is not confined to the hands and fingers, 

 but extends to the muscles and surface of the 

 fore-arms. And it was also remarked by the 

 same eminent physician, that in a case in 

 which the inside of the ring finger had been 

 wounded by a blunt needle, and a partial 

 anaesthesia induced, the same effect was per- 

 ceived in the little finger (alike supplied by the 

 ulnar nerve), obviously through the extension 

 of the paralysing influence towards the centre, 

 so as to affect the trunk higher up than the 

 point at which its branch to the little finger 

 was given off. Dr. Graves further cites, as 

 an example of anaesthesia having its seat in 

 disordered nutrition of the peripheral nerves, 

 and gradually advancing along their trunks 

 towards the centres, the curious Epidemic de 

 Paris, which occurred in the spring and sum- 

 mer of 1828. " It began (frequently in per- 

 sons of good constitution) with sensations of 

 pricking and severe pain in the integuments 

 of the hands and feet, accompanied by so 

 acute a degree of sensibility, that the patients 

 could not bear these parts to be touched by 

 the bed-clothes. After some time, a few days, 

 or even a few hours, a diminution, or even 

 abolition of sensation took place in the affected 

 members ; the}' became incapable of distin- 

 guishing the shape, texture, or temperature of 

 bodies, the power of motion declined, and 

 finally they were observed to become al- 

 together paralytic. The injury was not con- 

 fined to the hands and feet alone, but, ad- 

 vancing with progressive pace, extended over 

 the whole of both extremities. Persons lay 

 in bed powerless and helpless, and continued 

 in this state for weeks and months. Every 

 remedy which the ingenuity of the French 

 practitioners could suggest was tried, and 

 proved ineffectual. In some, the stomach 

 and bowels were deranged, and this affection 

 terminated in a bad state of health, and even 

 in death; in others, the vital organs, cerebral, 

 respiratory, and digestive, were in the same 

 state as before their illness, and their appetites 

 were good, but still they remained paralytics. 

 At last, at some period of the disease, motion 

 and sensation gradually returned, and a re- 

 covery generally took piace, although, in some 

 instances, the paralysis was very capricious, 

 vanishing and 'again re-appearing. In the 

 fatal cases, no evidence could be obtained, 

 from the most diligent search, of any lesion, 

 functional or organic, in the brain, cerebellum, 

 or spinal marrow."* These phenomena are 



* Op. Cit. p. 504. 



scarcely explicable on any other hypothesis 

 than that of some general cause (probably a 

 morbid matter circulating in the blood) affect- 

 ing the nutrition and functional activity of the 

 nerve-trunks, rather than of their centres. 



That anaesthesia may proceed from various 

 causes whose operation is limited to the sen- 

 sorial centres, is a matter of every-day ex- 

 perience. It is, however, where they have 

 suffered from some obvious lesion of a com- 

 paratively restricted character, that the proof 

 of this is most complete ; for although there 

 is strong ground for believing that the ordi- 

 nary operation of anaesthetic agents and nar- 

 cotic poisons is confined to the cerebrum and 

 sensorium, yet we could not positively affirm 

 such to be the case, since, when taken into 

 the blood, they may act not only on the sen- 

 sorial centres, but on the entire nervous 

 system. All the phemomena of narcoctic 

 poisoning, however, indicate that opium, al- 

 cohol, &c., single out the cerebrum and sen- 

 sory ganglia for their special action, just as 

 strychnia singles out the spinal cord ; the 

 suspension of the functional activity of the 

 former being usually complete, before there is 

 the slightest affection of the latter. That a 

 failure of the circulation in the encephalon 

 produces complete and universal anaesthesia 

 while it lasts, was fully proved by Sir A. 

 Cooper's well-known experiment; and it 

 seems probable that many of the structural 

 lesions which manifest themselves in paralysis 

 of motion and sensation produce this suspen- 

 sion of functional power in parts not them- 

 selves affected by disease, chiefly in virtue of 

 the derangement of the intra-cranial circula- 

 tion which they invole. 



There is one of the phenomena of the anaes- 

 thesia produced by the accidental or inten- 

 tional introduction of poisonous substances 

 into the blood, which seems deserving of more 

 special notice ; viz., the suspension of the 

 power of receiving painful impressions, with- 

 out the obliteration of the ordinary tactile 

 sensibility. This is a frequent resuft of the 

 exhibition of ether and chloroform ; and does 

 not seem to depend upon a mere blunting of 

 the ordinary sensibility. It has been especi- 

 ally noticed, also, in cases of lead poisoning, 

 in which state it seems to be more frequent 

 than complete anaesthesia. According to M. 

 Beau, the insensibility to pain, which he terms 

 analgesia, may be observed in a large propor- 

 tion of cases of " saturnine intoxication." 

 " We must not confine ourselves," he remarks, 

 " to asking the patient whether he feels, but 

 limit our question to the sensation of pain. 

 Parts which are thus insensible to pain are so 

 also to tickling. This form of anaesthesia may 

 affect the entire surface, being, however, most 

 remarkable in the extremities, and especially 

 the upper ones. It may extend even to the 

 mucous membranes, and especially those 

 which are normally endowed with great sen- 

 sibility, as the uvula, isthmus faucium, 

 nares, or conjunctiva, any of which parts 

 may be tickled without the usual conse- 



