We can more readily watch the development of successive symptoms, which arise from the slight and insufficient admission of oxygen to the lungs, than where there is entire cessation of breathing. In the latter case fatal effects follow so speedily as to give us but little time for observation. The following external phenomena present themselves in cases of impeded respiration. The first sensation is one of distress about the region of the lungs, accompanied with violent struggles for breath, in which there is an involuntary effort to expand the chest by bringing into action the intercostal muscles, the diaphragm and all the muscles connected with breathing. These struggles become exceedingly violent and almost convulsive, and are accompanied with a sensation of extreme agony. This agony, however, is of short duration being speedily followed by a torpor, which gradually deprives the sufferer of all consciousness. The struggles, however, continue, assuming the form of convulsions both of the trunks and limbs, in which nature seems to be making giant efforts for freedom, and to burst the fetters which are every moment pressing stronger and stronger on the seat of life. During these struggles the lips and face become blue and livid; the veins in the head swell until they stand out like chords; the eyes become bloodshot, and seem as if starting from the head. At length the convulsions subside into a scarcely perceptible twitching of the limbs, and this soon ceases, and is followed by a fatal immobility. The muscles relax, and even the sphincter which retain their irritability to the last moment, give way. The pulse is still perceptible, and the heart flutters for a moment longer, contracting feebly and with quick vibrations. In a few moments this also stops, and the circulation ceases. Now is the time when life is almost extinct, the lamp has gone out, leaving but a faint spark, and unless immediate and the most energetic measures are resorted to, no human power can fan that spark into a flame, and bring back warmth and life to the cold and torpid body. When asphyxia is more gradually induced, the sufferings are more protracted. The painful sense of anxiety is accompanied with vertigo, humming in the ears, scintillations before the vision, and various phenomena The extinction of irritability is gradual, and is not attended with epileptic convulsions. There is a greater discoloration of the body but less of face.

Asphyxia, causing sudden death, is not generally witnessed in disease, but more frequently occurs in accidents. In chronic as well as acute cases, there is oftentimes a tendency to asphyxia for some little time. In these cases we see a gasping for breath, energetic and violent action of the muscles, livid looks, blood-shot eyes, dilated pupils, an expression of extreme agony, cold sweat, frequently delirium and those various phenomena we observe in shorter cases, showing that the blood is imperfectly arterialized. Examination after death gives us the same condition of the heart and blood-vessels as in shorter cases.

Death by coma as well as asphyxia is very common. In the former case certain morbid states of the brain produce stupor, the respiration becomes slow, irregular and stertorous, the functions of the nerves which produce the movement of the throat fail, the chest ceases to expand, the blood is no longer secreted and death ensues. The difference between death by coma and asphyxia is this - in the former case sensibility ceases first, then the movement of the thorax, and consequently the action of the lungs; in the latter case the chemical function of the lungs ceases first.

Signs indicating the approach of death. There is often near the termination of life a comparative pause in the progress of the disease, when the mind emerges from the clouds which have hung around it, and shines with its accustomed brightness, and all physical suffering seems to have subsided. This is sometimes called the "lightning" before death, and is frequently viewed by friends with joy, who think they see in that delusive calm - death's herald, a sign of returning health. The amendment is not real, unless the pulse has improved; the energies of life are otherwise worn out, and the lamp is only flashing up for a moment, before it goes out in darkness. When sensibility to outward impressions is lost, and the mind is either delirious or darkened by the mists of death, scenes which have been strongly impressed on the mind, may reappear and again pass before mental vision.

Dr. Armstrong departed delivering medical precepts. Lord Tenderden, who passed straight from the judgment-seat to his death-bed, fancied himself still presiding at a trial, and expired with "Gentlemen of the jury, you will now consider of your verdict." Dr. Adam, the author of the Roman Antiquities, imagined himself in school, and Uttering the then touching and expressive words - "But it grows dark - the boys may dismiss," instantly died. He mistook the darkness of death which was casting its film over his eyes, and the eternal rest on which he was entering, for the shades of evening and the welcome rest which they bring. Before the spirit of Napoleon, in his last moments was moving the mighty panorama of the past. He was again on the battle-field, at the bridge of Lodi, struggling by the Pyramids; the thunder of battle was in his ears, and as there passed before his eyes that mighty army he had so often led to victory "Tete d'armee" broke from his dying lips.

The symptoms indicating the near approach of death are not always the same. Some in their last moments toss the clothes from the chest, as if their weight was uncomfortable, and though the attendants anxious to carry out their own ideas of comfort, and not permit the dying to contract a cold, are resolute in replacing them, they are as often thrust back. The patient is often unconscious of his acts, yet they indicate that the weight of the clothes is insupportable, and it is only a mistaken kindness to replace them, when he is using his utmost efforts to cast them aside. Too often are the dying surrounded by friends, who cluster around the bedside, forgetting, that to him every breath of air is a precious boon, and by their sobs and lamentations torture and agonize the soul in its last moments. The hearing is often painfully acute, even when the patient is supposed to be in a state of insensibility, and the frantic bursts of agony from weeping friends are often to the dying, although they may be unable to express it, the bitterest ingredient in their cup of death. Others pick the sheets or work them between their ringers. This may be to excite by friction the sense of touch or the restlessness produced by excited nerves. The functions of the eye become disordered, and black spots or motes and various illusions float before the vision, which the patient attempts to clutch with his hand, or brush away. Many, on beholding these symptoms, look upon them as an infallible sign of death, but in this they are sometimes mistaken.