CHLOROFORM is a colorless, heavy, volatile liquid; having a fruity ethereal odor and a sweet pungent taste. It is formed by the union of chlorine and marsh gas, but more commonly by the action of bleaching powder on ethylic or methylic alcohol. It is readily soluble in alcohol, but very sparingly so in water. Chloroform is a good solvent of caoutchouc, gutta-percha, camphor, wax, resin, some of the alkaloids, &c. The _symptoms_ produced by the vapor of chloroform may be divided into three groups of varying intensity; briefly they are these: First, a degree of relief from pain, the senses being but slightly affected; second, a stage of excitement and incoherence, wherein the patient is prone to struggle; and thirdly, a stage of which the most marked features are complete insensibility and narcotism, with relaxation of the muscular system. At first the patient is conscious of all that is passing around him, but there is dizziness and singing in the ears. Then the mental functions are impaired, there is often excitement, the saliva is increased, the patient pushes away the inhaler, rigidity and spasms of the muscles may occur, and there is incoherent talk. In the next stage there is insensibility to pain, and the conjunctiva may be touched without causing flinching. If the use of this anæsthetic be pushed further the breathing becomes stertorous, the muscles quite relaxed, and the pupils dilated; while a still further increase of the chloroform embarrasses and then stops the breathing and arrests the heart’s action. Many cases of death from the vapor of chloroform have occurred, the fatal effect sometimes happening very rapidly from shock, syncope, or convulsions. The vapor of only thirty drops has destroyed life in one minute. Death under the influence of chloroform must not be confounded with death from its effects. The smallest fatal dose when the drug has been swallowed is one drachm in a boy aged four.