Sulphuric Ether.—Sulphuric ether, or ether, is a clear colorless liquid, very inflammable, soluble in alcohol, and less so in water. It is usually obtained by distilling common alcohol with sulphuric acid.
The effects produced by the inhalation of ether are similar to those which result from chloroform. It is, however, without doubt a much safer agent, but its effects are longer in manifesting themselves; it is more irritating to the air-passages, and much more of it is required. Deaths have occurred under its influence as under that of chloroform.
Amylene.—This is a colorless, volatile liquid, made by distilling amylic alcohol (obtained from crude fusel oil, or oil of potato spirit) with chloride of zinc.
Dr. Snow found that amylene, like chloroform, is capable of causing sudden death by inducing over-narcotism of the heart, and paralysis of this organ. He had two deaths from it, and it has since been entirely given up as an anæsthetic.
Nitrous Oxide.—Comparatively recently the laughing gas of Sir Humphrey Davy has been introduced as an anæsthetic agent. Its successful use depends on the total exclusion of air from the lungs during its exhibition. It can only be used for a short time, hence it is chiefly employed in dental operations, although it has been given for a considerable length of time consecutively by allowing the patient to return to the verge of sensibility before giving a fresh dose.