TOUCH, 525 



line from the ear to the upper or under lip, they will feel more 

 and more distant from each other as they approach these. 



If the points of the compass, kept at the same distance from 

 each other, are applied to two contiguous surfaces, enjoying vo- 

 luntary motion, as to the two lips, they will appear more distant 

 than when applied to one surface : in fact in the case of the lips, 

 though, when distant from each other half a line, they appear as 

 two, yet, if applied to one lip only, they appear as one. Nay 

 the points, though at the same distance from each other, will seem 

 more distant when applied to two portions of the skin differing in 

 structure and function, than when applied to portions resembling 

 each other, even though more sensible. Thus, if the points are 

 placed one upon the inner surface, and one upon the red outer part 

 of the lips, they appear more distant from each other than when 

 both are applied, though at the same distance, on the outer red 

 surface which is so much more sensible. 



When the points of the compass are placed horizontally on the 

 axis of a limb, they are distinguished as two more clearly than 

 when placed vertically. But the reverse occurs, if they are placed 

 on the trunk. 



He finds the left hand more sensible of temperature than 

 the right in most persons, probably from its epidermis be- 

 ing thinner through less use. When the hands, being of the 

 same temperature, were plunged into separate vessels of hot 

 water, as the person lay in bed, the left hand was believed to 

 be in hotter water, though the temperature was two degrees 

 lower than that of the water in the other vessel. A difference of 

 one third of a degree is readily detected by the hand if placed 

 successively in two vessels of water. The judgment is more ac- 

 curate when the temperature is not much above or below the 

 usual temperature of the body ; water at 98 being more readily 

 distinguished from water at 100, than water at 120 from water 

 at 118 ; just as sounds are best discriminated when neither very 

 acute nor base nor loud. A large surface receives stronger impres- 

 sions than a smaller. If the forefinger of one hand is immersed 



I have always been struck with the erroneous judgment I form of the spot 

 of the trunk, or arras, or legs, in which an itching or tingling is felt. So 

 satisfied in general am I that I cannot put my finger on the spot where I feel 

 the tingling, unless I use my eyes, that I have frequently amused myself with 

 observing what a blunder I was sure to make. 



