SENSE OF TASTE. 733 



parison, the Author may mention the case of a blind friend of his own who 

 has acquired a very complete knowledge of Couchology, both recent and 

 fossil ; and who is not only able to recognize every one of the numerous 

 specimens in his own cabinet, but to mention the nearest alliances of a shell 

 previously unknown to him, when he has thoroughly examined it by his 

 touch. Many similar instances might be cited, one of the most remarkable 

 being that of John Gough, who, although blind, was a noted botanical col- 

 lector, aud earned his livelihood as a land-surveyor. Several cases are on 

 record 1 of the acquirement by the blind of the power of distinguishing the 

 coA>r.s- of surfaces which were similar *iu other respects, and, however wonder- 

 ful this may seem, it is by no means incredible. For it is to be remembered, 

 that the difference of color depends upon the position aud arrangement of 

 the particles composing the surface, which render it capable of reflecting 

 one ray whilst it absorbs all the rest ; aud it is quite consistent with what 

 we know from other sources, to believe that the sense of Touch may become 

 so refined, as to communicate a perception of such differences. 2 



3. Sense of Taste. 



599. The sense of Taste is that by which we distinguish the sapid proper- 

 ties of bodies. The term as commonly understood, includes much more 

 than this; being usually employed to designate the whole of that knowledge 

 of the qualities of a body (except such as is purely tactile), which we derive 

 through the sensory apparatus situated within the mouth. But it will be 

 hereafter shown that a considerable part of this is depeudeut upon the assist- 

 ance of the olfadive sense ( 603) ; which is affected, through the posterior 

 nares by the odorous emanations of all such bodies as are capable of giving 

 them off; aud the indications of which are so combined with those of the 

 true gustative sense, as to make an apparently single impression upon the 

 Sensorium. Moreover, there are certain sensorial impressions received 

 through the organ of taste, which are so nearly allied in their character to 

 those of touch, as to render it difficult to specify any fundamental differ- 

 ence between them ; such are the pungent sensations produced by mustard, 

 pepper, the essential oils, etc. ; all of which substances, when applied for a 

 sufficient length of time to any part of the cutaneous surface, produce a 

 sensation which can scarcely be distinguished from that excited through the 

 organ of taste, in any other way than by its inferior intensity, and by the 

 absence of the concurrent odorous emanations. The taste of such substances 

 might therefore, perhaps, be considered as the composite result of the im- 

 pressions made upon the sensorium through a refined and acute touch, aud 

 by the effect of their odorous emanations upon the organ of smell. After 

 making full allowance, however, for all such as can be thus accounted for, 

 there remains a large class of pure sapors, of which we take cognizance 

 without the assistance of smell, and which are altogether dissimilar to any 

 tactile impressions ; such are the bitter of quinine, the sour of tartaric acid, 

 the sweet of sugar, the saline of common salt, etc. The smell can give us no 

 assistance in distinguishing small particles of these bodies, since they are 



1 Among the best-authenticated of these, is that of a lady who became blind, and 

 afterwards deaf, in consequence of an attack of confluent small-pox; cited in 

 Dr. Kitto's Lost Senses, vol. ii, p. 79, from the Annual Register for 1758. Dr. Kitto's 

 treatise may be referred to, as containing a large collection of interesting cases of a 

 similar description. 



2 For some additional details in regard to the sense of touch, see the Author's 

 article Touch, in the Cyclopedia of Anatomy and Physiology, vol. iv. 



