The memoir which I have now the honour of presenting to the Society contains part of a continued investigation, of which the first results were published in a paper read, last year, before the Chemical Society of London. The nature of the materials experimented on is such, and the scope of the subject so large, as to afford nothing more to all I have at present brought to light than the name of a bare and partial outline; yet the facts I have now to adduce, of some interest in themselves, will increase that of those already made known, and prove of additional service in aiding to complete that desirable object, a knowledge of the chemical constitution of the natural bases. In the paper alluded to, I shewed that, by the action of iodide of ethyl and of methyl upon morphia and codeine, the two most prominent alkaloids of opium, new salts are produced, in which the basic molecules appear to assimilate by their chemical characters to the hypothetical metal ammonium, or its oxide rather; so that, in the system of Hofmann, these peculiar results of natural, and as yet inimitable agencies, would take rank among the nitryle bases.