Such being the nature of the sources from which we must draw our information, we shall obtain a better general view of the whole subject if we depart from the practice of former chapters, and follow out the more important questions in their historical development instead of connecting them directly with leading persons. Such a treatment of the subject is indeed suggested by the fact that we are now no longer on pure historic ground; for the majority of the men who have developed modern doctrines since 1840 are still alive, and it must be uncertain whether the account here attempted may not be impugned on some ground or other. Owing to the extraordinary diversity of opinion that exists among botanists even on the most general questions in the science, it is extremely difficult to ascertain what can be considered as a common possession,—an unfortunate condition of things, from which no science perhaps suffers so much as botany. The extent to which individual botanists have contributed to the advance of phytotomy during the period under consideration will appear of itself from the following narrative; and if we speak almost exclusively of Germans, it is for the simple reason that Englishmen from Grew’s time till now can scarcely be said to have added anything to our knowledge of phytotomy; the Italians also, once so gloriously represented by Malpighi, scarcely come under consideration in the questions now to be dealt with, while French botanists, represented by Mirbel in the preceding period, though they have produced many works on phytotomy since his time, have had no important share in deciding the fundamental questions of modern science.