Conversations on Vegetable Physiology

Conversations on Vegetable Physiology is a popular science book by Jane Marcet, first published in 1829. It is one of the later books in her long series of popular educational works, which had begun in 1805 with the enormously successful Conversations on Chemistry and which had extended through Natural Philosophy, Political Economy, and several other subjects across the following two decades. By the time the Vegetable Physiology book appeared, Marcet was an established figure in English popular science writing and her conversational method was well known.

The book applies the familiar Marcet format to the new and developing subject of plant physiology. There is the teacher Mrs B and her two pupils, Emily and Caroline, who learn the principles of botany and plant science through a long series of conversations. The subjects covered are the standard early nineteenth century botanical curriculum, with some attention to the more recent work on plant chemistry and physiology that had emerged in the previous generation. There are chapters on the parts of plants, on the functions of leaves and roots, on the circulation of sap, on flowering and seed production, on photosynthesis as it was then understood, and on the various practical applications of plant science to agriculture and horticulture.

Marcet had been in close contact with leading botanists during the years she was preparing the book, and the science is generally up to date for the late 1820s. The book benefits from the same qualities that made her chemistry and physics books so successful. The questions Emily and Caroline ask are the natural questions of beginning students. The answers Mrs B gives are clear and accurate. The illustrations, important in a botanical text, are well chosen and clearly drawn.

The book runs about three hundred and fifty pages and is best read chapter by chapter rather than straight through. Much of the science is now out of date, since plant physiology was transformed by the mid nineteenth century work on photosynthesis and respiration that Marcet’s book partly anticipated but could not yet incorporate. For readers interested in the history of botanical education in English, the book remains valuable as a snapshot of how the subject was being taught to beginning students in the late 1820s. It pairs naturally with Marcet’s other popular science books and with the more advanced botanical works of her contemporary John Lindley.