You have experienced the sensitiveness to cold of the pulps of the fingers and toes; and have, probably, remarked that it is more difficult to keep them warm than any part of the body. I may add that, notwithstanding the liberal allowance of the means of supporting life (that is, blood and nervous influence) which they enjoy, they are very liable to mortify from frost-bite and other causes. I have repeatedly known that to happen when all the rest of the hand has escaped. This must be attributed, perhaps entirely, to their exposed position as terminal parts; and they share their susceptibility to cold with other parts similarly circumstanced, such as the nose, the elbows, the knees and the buttocks. It is necessary to make a distinction between the SENSE OF TOUCH and common FEELING or sensitiveness to pain; for they are not quite the same. They are, it is true, very nearly alike, so nearly that we may consider them to be modifications of one another; and it is probable that the same nerves minister to both. Still there is a difference. The sense of touch is the sense of contact with _ex_ternal bodies, and enables us to take cognisance of their presence and inform ourselves of their shape, consistence, smoothness or roughness, &c.; whereas common sensation, or the sense of feeling, has an _in_ternal relation. It imparts to us information respecting the condition of our own bodies or any part of them. By the sense of touch in the tongue, for instance, we judge of the size and hardness of the morsel in the mouth; and by common sensation we learn that the organ is being bruised or scratched by it. Sensation of pain commonly destroys the sense of touch. Put your finger into a vice, and you may feel both sides of it. Screw it up, and you have nothing but the sensation of pain. If you were to awake in this state you would not, from the mere sensation, know that you were _touching_ anything. As a general rule there is a relation between the degree in which sensation and the sense of touch are manifested in different parts of the body. For instance, I have just been remarking on the acuteness of the sense of touch in the Tongue; and we know that this part is very sensitive to pain. The pain caused by a bite of the tongue is horrible; and so effectually does it serve the good end of warning the tongue to keep within its proper bounds, that that organ very rarely suffers from the pressure of the teeth. But, forasmuch as sensitiveness to pain serves a different purpose from the sense of touch, namely, as in the instance of the tongue just mentioned, it renders parts alive to injurious impressions, and gives them warning to escape or protect themselves; so it is, as we might expect, most manifested in those surfaces where a slight amount of injury would prove most detrimental.