Darwin's idea of evolution surfaced in several of his other works. In the "Loves of the Plants" (1789), reprinted in several editions as "The Botanic Garden", there occurs the comment: "Perhaps all the productions of nature are in their progress to greater perfection!". All these natural history works are in the form of poems, and so they are not satisfactory from the point of view of modern science. But the 18th century was a time when intelligent men made connections; the specialist types of scientist occurred first in the lifetime of his grandson Charles.