X. I cannot close this short account of the origins, which have been attributed to man during late years, without mentioning the new theory which has lately been put forward by an eminent botanist, to whose works I have often had to allude. M. Naudin has been one of the most important of Darwin’s precursors. Six years before the English naturalist, he compared the action exercised by natural forces in the production of _species_ to the methods used by man in obtaining _races_; he admitted the _derivation_ and _filiation_ of species; he compared the vegetable kingdom to a tree “where roots, mysteriously hidden in the depths of cosmogenic time, have produced a limited number of branches successively divided and sub-divided. The first branches represent the primordial types of the kingdom, the subsequent ramifications the existing species.” We cannot fail to recognise in these words an idea very similar to Darwinism. M. Naudin now proposes an _evolution theory_ which is very different. He “entirely excludes the hypothesis of natural selection, unless the sense of the word is changed so as to make it synonymous with _survival_.” He rejects no less strongly the idea of _gradual transmutations_, which require millions of years to effect the transmutation of a single plant. He insists, on the contrary, upon the _suddenness_ with which most of the variations observed in plants have been produced, and regards it as a representation of what must have taken place in the successive genesis of living beings. Let us remark in passing, that Darwin, in the last edition of his work recognises the reality of these _sudden leaps_, which have taken place without transitions between one generation and another, and confesses that he has not taken sufficient account of them in his earlier writings.