CHAP, xiv.] OF TOUCH. 403 



Most parts of the frame have their several feelings of comfort 

 and pleasure, of discomfort and pain. In many of the more deeply 

 seated organs no strong sensation is ever excited, except in the 

 form of pain, as a warning of an unnatural condition. The inter- 

 nal sensations of warmth and chillness, of hunger, thirst, and their 

 opposites, of nausea, of repletion of the alimentary and genito- 

 urinary organs, and of the relief succeeding their evacuation, of 

 the privation of air, etc., with the bodily feelings attending strongly 

 excited passions and emotions, may be mentioned among the 

 principal varieties of common sensation. 



The special sensations are referrible to five leading forms, and 

 are distinguished not less by their several modes or characters, 

 than by the more special and elaborate construction of the peri- 

 pheral parts of their respective organs, whereby these are adapted 

 to receive the impressions of their appropriate stimuli. The special 

 sensations excited through the instrumentality of the peripheral 

 organs of touchy taste, smell, vision, and hearing, are primarily 

 designed to inform the mind of the conditions of the external 

 world ; and it is for the most part only in a secondary manner, or 

 through the mind, that they operate on the organic functions, or 

 for the conservation of the body. 



Almost all sensation is attended with the idea of locality, 

 the mind referring the cause of the change it experiences to the 

 peripheral part of the sensitive apparatus excited. Thus the ideas 

 of distance, extent, and relative position, originate in the very con- 

 struction of our bodies, and soon become applied to the material 

 objects around us by the comparison of the impressions on our 

 different organs, and their several parts, with one another. The 

 abstract idea of space is a further conception of the mind. 



OF TOUCH. 



This is the simplest and most rudimentary of all the special 

 senses, and may be considered as an exalted form of common 

 sensation, from which it rises, by imperceptible gradations, to its 

 state of highest development in some particular parts. It has its 

 seat in the whole of the skin, and in certain mucous membranes, as 

 that of the mouth, and is therefore the sense most generally diffused 

 over the body. It is also that which exists most extensively in the 

 animal kingdom ; being, probably, never absent in any species. It 

 is, besides, the earliest called into operation, and the least compli- 



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