^94 On the fafcinating Faculty afcr'ihecL to 



of the nerves, and the celhtlar texture; the latter being com- 

 pbfed of cvHndric tubes, containing the former in their ca- 

 vity : and in thefe lubes, thefe flieaihs of the nerves, is the 

 feat of the power which continues the irritation of the mind 

 into the body. The medullary fuhltance of the nerves, on 

 the other hand, pofiefles no other power than that of exciting 

 in the fenforium fenfations correfponding with tlie imprei- 

 lions received by the fenfes. The cehular texture ot the 

 nerves pofTefles a power of contraftion, elalHcity; but the 

 medullary fubftance of the nerves polTefles only the fimple 

 fenfitive power of the nerves. From this, the above-men- 

 tioned phaenomena, tfpecially thofe obfervable in St. Vitus's 

 dance, are eafily explained. The fenfitive power of the nerves 

 diiappears, becaufe its organ, the medullary fubflance, is de- 

 firoyed or wounded. The two following arguments confirm 

 the correftnefs of this opinion : — i. Accordmg to Aaneman's 

 numerous experiments on the regeneration of the nerves, 

 each end of a nerve which has been cut in two forms itfelf 

 into a fcirrhus, and both afterwards join again in the cel- 

 lular texture; but the lower end of the nerve ihus intcrfet^ed 

 always lofes its fenfitive power, whereas it recovers in a few 

 months the power of motion when both the ends arc joined 

 again by a fufficienl quantity of the cellular fubftance. 

 a. Arfenic and all forts of mercurial preparations, when 

 immediately applied to the brain, exhibit not the leaft im- 

 mediate efl'cft upon it. But thofe very minerals, when ap- 

 plied in any other part, excite the moft violent convulfions 

 of the whole body ; and it is well known, from other circum- 

 ftances, that thefe produce the greateft irritation upon the 

 cellular texture. Without entering into any further elucida- 

 tion, every one will eafily conceive the great importance of 

 thefe ideas in the explanation of many phyfiological and pa- 

 thological phaenomena. 



LTV. Letter from Dr. Barton to Vrofeffor Zimmerm ann, 



on the fafcinating Faculty which has been afcribed to the 

 Rattlifnake, t.nd other American Serpents. 



[ConcluikJ from p. 202.] 



jTxFTER quoting Mr. MichaeTis's obfervations, which I 

 have already noticed, Mr. Blumenbach has the following 

 words : " I would, however, add another mode of explana- 

 tion from Dr. Barton's work itfelf, where he aflures us that 

 the refult of his inquiries, whether the rattlefnake creeps up 



trees 



