The infinity of effects from similar causes, has often been taken notice of in the works of the Creator. It would seem as if they had all been made after one pattern. The late discovery of the cause of combustion has thrown great light upon our subject. Wood and coal are no longer believed to contain a principle of fire. The heat and flame they emit are derived from an agent altogether external to them. They are produced by a matter which is absorbed from the air, by means of its decomposition. This matter acts upon the predisposition of the fuel to receive it, in the same way that stimuli act upon the human body. The two agents differ only in their effects. The former produces the destruction of the bodies upon which it acts, while the latter excite the more gentle and durable motions of life. Common language in expressing these effects is correct, as far as it relates to their cause. We speak of a coal of fire being _alive_, and of the _flame_ of life. The causes of life which I have delivered will receive considerable support by contrasting them with the causes of death. This catastrophe of the body consists in such a change induced on it by disease or old age, as to prevent its exhibiting the phenomena of life. It is brought on, 1. By the abstraction of all the stimuli which support life. Death from this cause is produced by the same mechanical means that the emission of sound from a violin is prevented by the abstraction of the bow from its strings. 2. By the excessive force of stimuli of all kinds. No more occurs here than happens from too much pressure upon the strings of a violin preventing its emitting musical tones. 3. By too much relaxation, or too weak a texture of the matter which composes the human body. No more occurs here than is observed in the extinction of sound by the total relaxation, or slender combination of the strings of a violin. 4. By an error in the place of certain fluid or solid parts of the body. No more occurs here than would happen from fixing the strings of a violin upon its body, instead of elevating them upon its bridge. 5. By the action of poisonous exhalations, or of certain fluids vitiated in the body, upon parts which emit most forcibly the motions of life. No more happens here than occurs from enveloping the strings of a violin in a piece of wax. 6. By the solution of continuity by means of wounds in solid parts of the body. No more occurs in death from this cause than takes place when the emission of sound from a violin is prevented by a rupture of its strings.