Darwin,[13] in 1868, considers Knight's supposition at length and while he does not positively accept it, yet lends it his support by quoting several authors who put forth proofs in favor of it. His most positive statement in discussing the theory referring to facts regarding the origin of the peach is: "The supposition, however, that the peach is a modified almond which acquired its present character at a comparatively late period, would, I presume, account for these facts." Carrière,[14] one of the most eminent French pomologists of the last century, is the chief French champion of the theory that the peach came from the almond and devotes several pages in his estimable work, _Variétés De Pêchers_, in demonstrating that the one is a form of the other. His arguments, however, are but amplifications of those of Knight and Lindley though he cites more intermediate forms than either of the English writers--so many that they go far toward convincing one of the correctness of his views. There is the feeling, however, in the case of Carrière, in the light of present knowledge, that his botanical evidence is pushed a little too far for full credulity. Knight, Lindley, Rivers, Darwin and Carrière, the men holding the theory whose opinions are most worthy consideration, fell into error, as we think, through attaching too much importance to likenesses in the fruits of the peach and almond and because they became confused in following the behavior of the two fruits under hybridization. As we shall show later in discussing the characters of the peach, this fruit differs from the almond in other characters than those of the fruit--characters not at all likely to be changed by cultivation and selection as would all those of the fruits. Knight's proof from hybridization was purely speculative. The fact that the peach and almond may be crossed, giving intermediate forms, nowadays would not be looked upon as proof that the two necessarily belong to one species. However, in the light of the knowledge in existence at the beginning of the last century regarding the crossing of plants, we need not apologize for the inference that Knight drew from his simple experiment. Students of heredity would find almost conclusive proof that the peach is not a modified almond--a descendant, say, in this geologic period at least--in the fact that there is no recorded case of a peach fertilized by a peach producing an almond, or _vice versa_. If the relationship were at all close, if the two species had had a common origin even though in rather remote times, if they were nearly enough related readily to hybridize or be hybridized, it would be expected that now and then, as in the case of a nectarine, the peach would produce an almond or the almond a peach.