It is scarcely necessary that I delay you now with an account of all of the other ethereal anesthetic agents which have from time to time been advocated since the memorable days to which I have devoted most of my time to-night. Two only are at present ever thought of--namely, bichloride of methylene and bromide of ethyl!--and these are used by only a few, though each has its advantages. It is well known that nearly all of the ethers have more or less of anesthetic property, coupled with many dangers and disadvantages. Sulphuric ether and chloroform hold the boards to-day as against any and all of their competitors. Nitrous oxide gas, as already mentioned, was known to and used by Wells, in Hartford. With the advent of ether this gas fell at once into disuse, to be revived some fifteen years after the death of Wells, mainly through the use of Dr. G. Q. Colton. Since this time its use has been quite universal, although confined for the main part to the offices of dentists. Its great advantages are ease of administration and rapidity of recovery, making it especially useful for their purposes, while the difficulties attendant upon prolonged anesthesia by it makes it less useful for the surgeon. I will spend no further time upon it nor upon the subject save to do justice to modern anesthesia by a very different method and by means of a very different drug, which is to-day in so common use that we almost forget to mention the man to whom we owe it. I allude to _Cocaine_ and its discoverer, Koller. Cocaine is now such a universally recognized local anesthetic that there is the best of reason for referring to it here--the more so because it affords another opportunity to do honor to a discoverer, who has rendered a most important service to not only our profession, but to the world in general.