Then follows the _Discours Preliminaire_, comprising over a hundred pages, while the main body of the work opens with the _Principes Elementaires de Botanique_, occupying 223 pages.

The work was a general elementary botany and written in French.

Before this time botanists had departed from the artificial system of Linne, though it was convenient for amateurs in naming their plants.

Jussieu had proposed his system of natural families, founded on a scientific basis, but naturally more difficult for the use of beginners.

To obviate the matter Lamarck conceived and proposed the dichotomic method for the easy determination of species.