150 PLANT HYBRIDIZATION BEFORE MENDEL 



"For it is only after having determined the normal amplitude of these 

 variations that one is able to judge if more considerable ones present 

 themselves, which one is able to attribute with certainty to the action 

 of the causes of perturbation which one studies." (8, p. 3.) 



Vilmorin's scientific point of view is plainly shown in the fol- 

 lowing statement : 



"The number of forces which are in play is so considerable, the man- 

 ner in which they are able to combine is so varied, that it explains to 

 me in part how difficult it is to obtain completely concordant results in 

 an experiment where all the influences, save that which one studies, 

 ought to remain invariable." (8, p. 4.) 



In the following, Louis de ^'ilmorin shows an appreciation, in 

 advance of its scientific demonstration by Johannsen, of the prin- 

 ciple of using pure-bred strains or "pure lines" in breeding; of 

 breeding from the individual plant, and not by means of mass 

 selection. Referring to the breeding of the sugar beet, he says : 



"All that I have been able to observe up to the present, on the question 

 of the transmission by heredity of characters in plants, makes me think 

 that it is necessary to individualize the observations as much as possible. 

 So I have adopted the custom, when I had to fashion a race, no matter 

 how little rebellious, of gathering and sowing the seed separately of 

 each one of the individuals which I have marked as my choice, instead 

 of making, as ordinarily, a choice composed of as many individuals as I 

 needed to collect the quantity of grain of which I had need, and I have 

 always remarked that among these individuals there were some which 

 always gave a better return than others, and which I finally adopted as 

 the sole type for amelioration." (8, p. 18.) 



In 1890, Henry de Vilmorin reported (jd) an interesting obser- 

 vation with peas, similar in character to that of Goss, which 

 awakens surprise from its not having aroused further investiga- 

 tion. Speaking of the progeny, he says : 



"All the seeds of the same plant are not rigorously alike among them- 

 selves. They differ, especially when the plant which has borne them 

 is of a mixed race, and has undergone, or is in the process of under- 

 going, modifications through the action of the environment in which it 

 ives. 



Vilmorin then, in the following words, anticipated the present 

 point of view regarding the distribution of characters. 



"The different characters which enter into the composition impress 

 themselves differently in the different seeds, and are reproduced in di- 

 verse combinations in the plants issuing from those seeds." 



He proceeds to give as an illustration, precisely the case of the 

 distribution of characters which formed part of Mendel's experi- 

 ment. 



