Schleiden however did not succeed in securing firm ground for the morphology of the Cryptogams as founded on the history of their development. His investigations into the morphology of the Phanerogams were more successful. His theory of the flower and fruit is an admirable performance for the time, even though we abandon his view of the stalk nature of placentas and some other notions, as we obviously must. As Robert Brown founded the history of the development of the ovule, so Schleiden founded that of the flower, and his example influenced other botanists. Soon investigations into the genesis of the flower was one of the chief occupations of morphologists, and the results of enquiry into development proved to be of great value for the systematic arrangement of the Phanerogams, especially when more exact attention was paid to the sequence of development in the organs of an inflorescence, to abortion, doubling and branching of the stamens, and to the like matters. Duchartre, Wigand, Gelesnoff and many others, were soon working in the same direction with great success. Payer deserves special mention for his enormous perseverance in examining the development of the flower in all the more important families in his ‘Organogénie de la fleur,’ 1857, and thus producing a standard work, distinguished alike for the certainty of the observations, the simple unbiassed interpretation of the things observed, and the beauty and abundance of the figures—a work which became more important every year for the morphology of the flower. Schleiden’s text-book was the first of its kind that supplied the student with really good figures based on careful observations. With all its many and obvious defects it had one merit which cannot be rated too highly; its appearance at once put botany on the footing of a natural science in the modern sense of the word, and placed it upon a higher platform, extending its horizon by raising its point of view. Botany appeared all at once as a science rich in subject-matter; Schleiden had not only himself made many investigations and broached new theories, but he everywhere drew attention to what was already before the world and was important; for it is not sufficient as regards the literature of a science that there should be good investigators; it is as necessary that the scientific public, and especially the rising generation of professed students, should be well and sufficiently instructed in the art of distinguishing important from unimportant contributions. It must be distinctly affirmed in this place, that if Schleiden’s theory of cell-formation, his strange notion about the embryology of Phanerogams and the like were very quickly shown to be untenable, this does not in the least affect the great historical importance which his writings possess in the sense here indicated.