60 TOUCH AND SENSATION* 



increasing the action of the cutaneous vessels and 

 nerves. 



Some mental emotions operate upon the skin, and 

 impair its functions much in the same way as cold. 

 Grief, fear, and the depressing passions, by dimin- 

 ishing the afflux of arterial blood, render the skin 

 pale, and at the same time diminish perspiration and 

 nervous action ; while rage, and other violent pas- 

 sions, by augmenting the afflux of blood, elevate the 

 temperature of the skin, and give rise to the red 

 flush, fulness, and tension so characteristic of ex- 

 citement. Facts like these establish a connexion 

 between the brain and the nervous system and the 

 skin, which it is important not to overlook. The 

 brain is readily admitted, by reflecting minds, to ex- 

 ercise much influence on the general system, be- 

 cause the nervous substance of which it is com- 

 posed is collected into one focus, and, thus united, 

 is seen to constitute a large mass. In reality, how- 

 ever, the nervous matter, spread out on the surface 

 of the body for the purposes of sensation, is so great 

 that many anatomists consider it as even exceeding 

 the mass of the brain, and hence its reverse influence 

 might be expected to be, as it actually is, of much im- 

 portance to health. 



We see this exemplified on exposure to intense 

 cold. The first sensation of chill on the nervous- 

 surface of the skin is speedily succeeded by that of 

 numbness and insensibility. The impression is 

 thence communicated to the brain, which in its turn 

 becomes affected, as is shown first by confusion of 

 mind, as noticed by Captain Parry, and afterward 

 by the total suspension of the mental powers, and 

 the extinction of life itself. When, on the other 

 nand, as in tropical climates, the surface is relaxed 

 by excessive heat, the brain speedily participates iit 

 ihe relaxation, and the mind is unfitted for sustained 

 or vigorous action. 



Invalids and literary men often suffer severely 



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