The morphology of the Japanese language has been explored most thoroughly within the confines of the language itself, as can be seen from the Nihon Bunpōron, one of the admirable publications of Professor T. Yamada's, and Mr. G. B. Sansom's excellent treatise, An Historical Grammar of Japanese. There are,nevertheless, various difficulties to be overcome, and many problems to be solved, if the ancient Japanese literature is to be better understood.Some of these obstacles have recently been pointed out by Professor J. L. Pierson in his scholarly work The ManyôŚû, in which the author has submitted many a plausible theory based on materials offered by the Japanese language alone.