A fixed nomenclature in biology has been found not only to be advantageous, but to be a prerequisite to progress in research, as the vast multiplicity of facts, still ever accumulating, would otherwise overwhelm the scholar. In philological classification fixity of nomenclature is of corresponding importance; and while the analogies between linguistic and biotic classification are quite limited, many of the principles of nomenclature which biologists have adopted having no application in philology, still in some important particulars the requirements of all scientific classifications are alike, and though many of the nomenclatural points met with in biology will not occur in philology, some of them do occur and may be governed by the same rules. Perhaps an ideal nomenclature in biology may some time be established, as attempts have been made to establish such a system in chemistry; and possibly such an ideal system may eventually be established in philology. Be that as it may, the time has not yet come even for its suggestion. What is now needed is a rule of some kind leading scholars to use the same terms for the same things, and it would seem to matter little in the case of linguistic stocks what the nomenclature is, provided it becomes denotive and universal. In treating of the languages of North America it has been suggested that the names adopted should be the names by which the people recognize themselves, but this is a rule of impossible application, for where the branches of a stock diverge very greatly no common name for the people can be found. Again, it has been suggested that names which are to go permanently into science should be simple and euphonic. This also is impossible of application, for simplicity and euphony are largely questions of personal taste, and he who has studied many languages loses speedily his idiosyncrasies of likes and dislikes and learns that words foreign to his vocabulary are not necessarily barbaric. Biologists have decided that he who first distinctly characterizes and names a species or other group shall thereby cause the name thus used to become permanently affixed, but under certain conditions adapted to a growing science which is continually revising its classifications. This law of priority may well be adopted by philologists. By the application of the law of priority it will occasionally happen that a name must be taken which is not wholly unobjectionable or which could be much improved. But if names may be modified for any reason, the extent of change that may be wrought in this manner is unlimited, and such modifications would ultimately become equivalent to the introduction of new names, and a fixed nomenclature would thereby be overthrown. The rule of priority has therefore been adopted.