of pain is so stationed as to prevent any attempt at change of identity. And it is a remarkable fact, that among the numberless devices to which criminals have resorted to prevent detection, we do not find a case recorded where this was attempted by an alteration of the features.

b3. Pain defends life.

will be ready

The delicious

§ 152. Let it be suspended, and we then enough to admit the value of its active aid. lull of the sensibilities which is experienced by those who yield to the drowsiness produced by extreme cold, indicates the approach of death, because it arises from the silencing of those sleepless monitors by whom the gates of life are guarded. Several parallel cases are recorded of persons who have laid down to rest in cold weather on lime-kilns, and who, stupefied by the carbonic acid, have either been killed by the heat, or have had their limbs partially consumed, of which fact, however, they were not aware until they attempted to use them. By patients who have had limbs removed when under the influence of chloroform, the same subsequent unconsciousness is exhibited. "A man who had his finger torn off," we are told by Sir Charles Bell, "so as to hang by the tendon only, came to a pupil of Dr. Hunter. I shall now see, said the surgeon, whether this man has any sensibility in his tendon. He laid a cord along the finger, and blindfolding the patient, cut across the tendon. Tell me, he asked, what have I cut across? Why, you have cut across the cord, to be sure, was the reply." Not only therefore is the action, but the location of pain, adjusted to warn against real danger, and then, when its office is completed, the watchman withdraws, inflicting no

further distress than is actually necessary to discharge his mission.

§ 153. We have another illustration of the importance of pain, in the mischief following its suspension, in the cases of those paralytics in whom sensibility is lost in the numbness. of disease, and whom, therefore, in order to prevent mortification of the flesh from the constant pressure produced by lying in one position, it is necessary constantly to move. In persons in health, nature performs the same office, at the promptings of pain, by those constant though unconscious movings by which even the deepest sleep is accompanied. c3. Pain economizes strength.

§ 154. Fatigue, for instance, is the grand protector of the muscular system against premature decay. An instance hast lately been mentioned of a chemist who, in order to perfect an experiment, kept himself awake and in the active exercise of his faculties for day and night during an entire week, but who dropped down dead at the close of this period, broken as it were to pieces in the same way that a spring breaks on which is placed a constant and unrelieved pressure. Such, to speak of the higher faculties of the mind, was the case with Hugh Miller, who plied a frame which in its earlier years was used only to physical labor, until at last, at the close of his final and most brilliant intellectual effort, the nervous system suddenly crashed.* "I have got rid of my headaches,” said a man of eminent talents in our own country not long since to a very capable observer, "and I can now work uninterruptedly." "You have got rid of

* See post, 157.

your safety-valves," was the reply, "and now prepare for an explosion." Pain thus guards the intellect from the invasion of excess; and if the sentinel is drugged into silence, the fortress is in danger.

§ 155. The same rule holds good with regard to the muscular powers. How vast, in the vivacity of youth, would be the springs, how violent the blows struck by the hands and feet, how protracted the exertion, were it not for this sense of pain that comes and says, "Stop here; this is too much for your strength; your hand or your foot will be crushed by that shock; your body will be dashed to pieces by that fall; your muscles will be worn out by those continued strains!" The sense of pain acts in this way as a sort of subsidiary agency to keep up the integrity of the animal system; and without it we would have men strewn along the stream of life in wrecks,-limbs crushed in, sinews sprung, shape deformed. And, by a singularly subtle contrivance, these functions of preliminary injunction against waste are vested just in the authorities who can most efficiently exercise them, and are vested nowhere else. Acting, as this power does, through a severe and summary discipline, it is no slight proof of the Divine wisdom, that it is so economized as to be vested only in those organs and in those quarters where its action is essential. Thus the muscles and ligatures, so necessary to the easy working of the limbs, and the cushions of cartilages in which the ends of the bones play, communicate no pain when cut, for against an incised wound, so far at least as is requisite to prescribe prudence on the part of the patient, they are protected. But it is otherwise with regard to strains and concussions, against

which the elastic skin, so sensitive to cuts, utters but slight protest, while they are greeted by the muscles and ligatures with a most clamorous outcry. The sprained foot, by which prudence in jumping and leaping is taught, is equally emphatic with the sore cut which tells us it is necessary to be cautious in the use of edged tools. And both serve a still higher purpose in preserving the identity and individuality of the human frame, and in checking empirical experiments. Euripides tells us that the daughters of Pelias, on prescription of Medea, who undertook to cure old age, cut their aged father up, and put the pieces in a caldron, expecting him thus to come out young. Had the instincts of pain given to Pelias himself been consulted, or had the head surgeon and her assistants been made the first subjects of the operation themselves, the experiment never would have proceeded.

§ 156. The same remarkable distribution of this precautionary police, each department of it in the location to which it is peculiarly adapted and nowhere else, is to be found in the throat and windpipe. The texture of the windpipe is insensible to cuts, against which exterior guards are appointed, but is keenly sensitive to the slightest speck or crumb that threatens to pass the orifice. Now, how are such invaders to be repelled? The practical answer is to be found in a most ingenious system of defences by which this main entrance is guarded. The epiglottis acts as a trapdoor, which lifts up during breathing, but flies immediately to during swallowing. Then there is an exquisite irritability in the slit at the mouth of the windpipe, so that at

the approach of the most insignificant assailant, it at once bristles up and slams to its door. As, however, this slip must open at the next breath into the lungs, it is necessary that a new set of guards should be set in motion, and this is effected by a sympathy between the upper vein of the windpipe and a reserve body of muscles below, who, in case of the invader passing the first defence, throw themselves. into a state of vehement and clamorous resistance, of which the well-known convulsive windpipe cough is the outer manifestation.

§ 157. d. The experience of pain, to limited agents, is necessary to the appreciation of pleasure.

It has been already observed how the common blessings of life pass by unnoticed. It is, in fact, an inseparable attribute of a limited being, that his attention, and power of relish and appreciation, with his other faculties, grow weaker in proportion to the period in which they are kept on the stretch, until at last they cease to exist altogether. This we know is the case with the eye, in which, if turned to a specific object for any length of time, the power of vision relaxes and is gradually dissipated. We have still more remarkable illustrations of this in the intellectual and nervous powers. Unintermitted attention to any specific object,suppose it be a chemical experiment, as in a case already mentioned, if it does not result in a torpor of the particular faculties exercised, is apt to produce general insanity. From this we may infer the principle that to enable the perception to continue acute and vigorous, its forces must be periodically recalled to receive their tone either in a period of tor