He was only fifty-four, but his best work was already done, and his remaining years, until his death in 1892, were those of patient and serene invalidism. He wrote some fascinating prose in this final period, and his cluttered chamber in Camden became the shrine of many a literary pilgrim, among them some of the foremost men of letters of this country and of Europe. He was cared for by loyal friends. Occasionally he appeared in public, a magnificent gray figure of a man. And then, at seventy-three, the "Dark mother always gliding near" enfolded him. There are puzzling things in the physical and moral constitution of Walt Whitman, and the obstinate questions involved in his theory of poetry and in his actual poetical performance are still far from solution. But a few points concerning him are by this time fairly clear. They must be swiftly summarized. The first obstacle to the popular acceptance of Walt Whitman is the formlessness or alleged formlessness of Leaves of Grass. This is a highly technical question, involving a more accurate notation than has thus far been made of the patterns and tunes of free verse and of emotional prose. Whitman's "new and national declamatory expression," as he termed it, cannot receive a final technical valuation until we have made more scientific progress in the analysis of rhythms. As regards the contents of his verse, it is plain that he included much material unfused and untransformed by emotion. These elements foreign to the nature of poetry clog many of his lines. The enumerated objects in his catalogue or inventory poems often remain inert objects only. Like many mystics, he was hypnotized by external phenomena, and he often fails to communicate to his reader the trance-like emotion which he himself experienced. This imperfect transfusion of his material is a far more significant defect in Whitman's poetry than the relatively few passages of unashamed sexuality which shocked the American public in 1855.