126 SIXTH KKI'OKT— 183G. 



" It may be remembered that this nerve was the only one of the sen- 

 sibility of which no demonstrable account could be rendered, no satis- 

 factory experiment having been made upon it beyond what led to a 

 mere negative result. It was freely exposed to view in an ass, irritated 

 and divided, but no response occurred indicative of any apparent func- 

 tion. No muscular fibres were made to quiver by pinching or bruising 

 the nen'e ; nor was any movement indicating pain observed ; and when 

 it was divided there was no apparent loss of any function. On the 

 contrary, when the lingual branch of the fifth nerve was irritated, 

 pain was expressed, and when it was divided, the surface of the tongue 

 was deprived of tactile sensibility : also, when the ninth nerve was 

 irritated, no sign of pain appeared, but the muscles of the tongue qui- 

 vered ; and when this nerve was divided, the voluntary motions of the 

 tongue were destroj'ed, and the animal was unable to use its tongue. 



" The evidences of the sense oi taste were not investigated at all, being 

 considered as satisfactorily demonstrated by Sir Charles Bell and M. 

 Majendie to be referable to the lingual branch of the fifth nerve. 



" Of the incorrectness of this hypothesis we never entertained a doubt 

 imtil the appearance in this country of Professor Panizza's details of a 

 course of experiments of ten years' standing upon the cerebral and spi- 

 nal nerves*. Dr. Craigie's translation of the professor's account of his 

 labours and results in the Ed. Med. and Surgical Journal is highly sa- 

 tisfactory, and leaves no doubt of the correctness of the experiments 

 detailed. 



" It has been gratifying to find that our results in reference to our 

 paper read at the Edinburgh Meeting, stand generally confirmed by 

 those of Panizza, with the important exception that the professor's 

 experiments supply the deficiency of ours regarding the glosso-pharyn- 

 gcal nerve, and explain the reason why we could not discover its sen- 

 sibility by simply irritating and dividing it, without reference to the 

 gustatory function of the tongue. 



" The professor found that although the surfaceof the tongue became 

 insensible to mechanical injury when the fifth nerves were divided, yet 

 the sense of taste remained evidently recognised by the rejection and 

 preference of certain substances. The ninth pair of nerves also being 

 divided, the sense of taste continued to be exercised as usual, whilst 

 the animal was thus deprived of the power of moving the tongue ; and 

 the glosso-pharyngeal nerve being divided, no sense of taste teas after- 

 wards recognised. ' The dog,' says Panizza, ' in which the glosso- 

 pharyngeal nerves were divided, having recovered from the state of 

 depression in which he was immediately after the operation, (the other 

 nerves remaining entire,) lajiped water, and ate as freely as if he had 

 suffered no injury, and afterwards mastication and deglutition were per- 

 fect ; but he had no other guide than smell in the choice of his food, 

 so that he swulloiced with the same readiness the most disgusting and the 

 most noxious, and the most agreeable and beneficial articles, provided 

 either they did not smell, or their odour was artificially disguised, or 



* See Ed. Med. and Stiry. Journal for January, 183G. 



