PLANT HYBRIDIZATION BEFORE MENDEL 339 



results which were quite like those of Knight, 'but Mendel believed 

 that he found constant numerical relationships between the types of the 

 hybrids.' 



"It has occurred no differently with De Vries and von Tschermak. 

 De Vries especially, in the lecture given on July 11, 1899, at the first 

 'Hybrid Conference in London,' on 'Hybridizing of Monstrosities,' and 

 which first appeared in April 1900 (Journ. Roy. Hort. Soc. 24:69), de- 

 scribed, although quite without the precise Mendelian formulation, the 

 hybrid between the smooth Melandrium album glabrum (M. preslii Opiz) 

 and the typically hairy race of Melandrium rubrum, which, with respect 

 to the hairiness, typically Mendelizes." 



Following is the paper of Correns entitled, "G. Mendels Regel 

 iiber das V^erhalten der Nachkommenschaft der Rassenbastarde," 

 Ber. d. d. bot. Ges. Vol. 18, published April 24, 1900 (2a). 



The paper opens as follows : 



"The latest publication of Hugo De Vries, 'Sur la loi de disjonction 

 des hybrides' [Comptes Rendus de L'Acad. des Sci., Paris, March 26, 

 1900], which I came into possession of yesterday, through the generosity 

 of the author, prompts me to the following contribution : 



"l also, in my hybridization experiments with races of maize and peas, 

 had arrived at the same result as De Vries, who experimented with 

 races of very different sorts of plants, among them also with two maize 

 races. When I had found the orderly behavior, and the explanation there- 

 for — to which I shall immediately return — it happened in my case, as it 

 manifestly now does with De Vries, that I held it all as being something 

 new. / then, however, was obliged to convince rnyself that the Abbot 

 Gregor Mendel in Briinn in the 6o'j, through long years of and very 

 extended experiments with peas, not only had come to the same result 

 as De Vries and I, but that he had also exactly the same explanation, so 

 far as it was at all possible in 1866." (2a, p. 1 ?8.) 



". . . The work of Mendel's, which is indeed mentioned in Focke's 

 'Pflanzenmischlinge,' but has not been adequately appreciated, and which 

 has otherwise scarcely found attention, belongs to the best that has been 

 ever written upon hybrids, in spite of numerous demonstrations which 

 no one can make in incidental matters, for example, in what pertains to 

 their terminology. 



"I have then not held it to be necessary to assure myself the priority 

 for this 'post-discovery,' through a preliminary contribution, but de- 

 cided to continue the experiments still further. I confine myself in the 

 following to a few statements concerning the results with races of peas." 

 {ib., p. 159.) 



"The races of peas are, as Mendel correctly emphasizes, precisely in- 

 valuable for the questions interesting us here, because the flowers are 

 not only autogamous, but also are exceedingly seldom crossed by in- 

 sects. I came upon these circumstances through my experiments on the 

 formation of xenias — which here gave only negative results — and fol- 

 lowed the observations further, when I found that here the 'regularity' 

 is much more evident than with maize, in which it had first come to 

 hand with me. 



