To Oliver Wendell Holmes we owe the term _anesthesia_, as generally employed and made to mean insensibility to pain, no matter how produced. A more strict definition would limit the term to conditions comprising not only insensibility to pain but loss of consciousness. For mere loss of sensation we should, strictly speaking, use the word _analgesia_. This is a distinction with a difference. Thus I have on rare occasions seen a patient under chloroform absolutely oblivious to pain but perfectly conscious, and chatting intelligently throughout the operation. This is a rare phenomenon, but has been noted by various observers. So after intraspinal cocaine injections we secure complete analgesia of the lower portion of the body, but not complete anesthesia, the former being what we are most anxious to produce. The discovery of anesthesia is essentially to America’s credit. Long, of Georgia, had produced anesthesia by ether as early as 1842; Jackson, of Boston, also claims credit for the discovery; but to Morton, a dentist of Boston, is undoubtedly due the honor of having introduced it for surgical purposes. The first public demonstration of its properties was made by Morton and Warren, October 16, 1846, in the Massachusetts General Hospital. Chloroform seems to have been exploited independently by Guthrie, of Sackett’s Harbor, N. Y., and Simpson, of Edinburgh, in 1847. It is a curious historical fact that the patient to whom Simpson meant first to administer chloroform in his clinic did not receive it because of some failure to have it on hand; she took ether instead and died, presumably of the anesthetic. Had she died under the influence of chloroform it would have been a serious setback to any general appreciation of its merits. Nitrous oxide is also an anesthetic for which America may take the credit. These are the three drugs in common use today, although there are others which are coming into general favor. It can be stated as an axiom that when a surgeon tries to abolish human sensibility, or pass an instrument through the human skin, he introduces elements of danger which can never be certainly and completely controlled--that is to say, the administration of an anesthetic is never to be undertaken as a trifling matter, but should be entered upon as carefully for a minor procedure as for a dangerous and prolonged operation.