Some plants cultivated for more than two thousand years are not now known in a spontaneous state. This can be accounted for on one of these two hypotheses; either these plants, since history has begun, have changed so entirely in form in their wild as well as in their cultivated condition that they are no longer recognized as belonging to the same species, or they are extinct species. In case they are extinct, this extinction must have taken place of course during the short period (scientifically speaking) of a few hundred centuries, on continents where they might have spread, and under circumstances which are commonly considered unvarying. This shows how the history of cultivated plants is allied to the most important problems of the general history of organized beings. The study of plants by our author is divided into those cultivated for their subterranean parts, such as roots, tubercles or bulbs; those cultivated for their stems or leaves; those cultivated for their flowers or for the organs which envelop them; those cultivated for their fruits, and those cultivated for their seeds. In the process of investigation we readily observe that De Candolle, who appears a master of the tools of research in every branch of study, has not only used botanical resources, but those of history and of travel, of archæology, pæleontology, and of philology. The wealth of learning lavished by the author on his work is sometimes almost bewildering. One of the most striking results of the author’s researches is that certain species are extinct or are fast becoming extinct since the historical epoch, and that not on small islands, but on vast continents without any great modifications of climate. M. De Candolle tells us that in the history of cultivated plants he has noticed no trace of communication between the peoples of the old and new worlds before the discovery of America by Columbus. The Scandinavians, who had pushed their excursions as far as the north of the United States, and the Basques of the Middle Ages, who followed whales perhaps as far as America, do not seem to have transported a single species. Neither has the Gulf Stream produced any effect. Between America and Asia, two transports of useful plants, perhaps, took place, the one by man (the batata, or sweet potato), the other by the agency of man or of the sea (the cocoanut palm). THE ADVENTURES OF TIMIAS TERRYSTONE. A Novel. By O. B. Bunce. New York: _D. Appleton & Co._