352 APPENDIX 



selection of the individuals for further crossing, and these were of 

 the possible thirty -two forms; with the second experiment — 



seventy -three plants resulted, which agreed throughout perfectly in 

 habit with the pollen parent; in their internal composition, however, 

 they must have been just as varied as the forms in the other experi- 

 ment. A definite selection was consequently only possible with the 

 first experiment; with the second the selection had to be made at 

 random, merely. Of the latter only a portion of the flowers were 

 crossed with the A pollen, the others were left to fertilise themselves. 

 Among each five plants which were selected in both experiments 

 for fertilisation there agreed, as the following year's culture showed, 

 with the pollen parent: 



In the first experiment, therefore, the transformation was com- 

 pleted; in the second, which was not continued further, two or 

 more fertilisations would probably have been required. 



Although the case may not frequently occur in which the dom- 

 inant characters belong exclusively to one or the other of the 

 original parent plants, it will always make a difference which of the 

 two possesses the majority of dominants. If the pollen parent has 

 the majority, then the selection of forms for further crossing will 

 afford a less degree of certainty than in the reverse case, which 

 must imply a delay in the period of transformation, provided that 

 the experiment is only considered as completed when a form is 

 arrived at which not only exactly resembles the pollen plant in 

 form, but also remains as constant in its progeny. 



Gartner, by the results of these transformation experiments, was 

 led to oppose the opinion of those naturalists who dispute the 

 stability of plant species and believe in a continuous evolution of 

 vegetation. He perceives 1 in the complete transformation of one 

 species into another an indubitable proof that species are fixed 

 within limits beyond which they cannot change. Although this 



i r« 



[" Es sieht " in the original is clearly a misprint for " Er sieht."] 



