336 Mendel's Experiments 



this class have to contend. A final decision can only be 

 arrived at when we shall have before us the results' of 

 detailed experiments made on plants belonging to the most 

 diverse orders. 



Those who survey the work done in this department 

 will arrive at the conviction that among all the numerous 

 experiments made, not one has been carried out to such an 

 extent and in such a way as to make it possible to determine 

 the number of different forms under which the offspring of 

 hybrids appear, or to arrange these forms with certainty 

 according to their separate generations, or definitely to 

 ascertain their statistical relations^. 



It requires indeed some courage to undertake a labour 

 of such far-reaching extent ; this appears, however, to be 

 the only right way by which we can finally reach the solu- 

 tion of a question the importance of which cannot be over- 

 estimated in connection with the history of the evolution 

 of organic forms. 



The paper now presented records the results of such 

 a detailed experiment. This experiment was practically 

 confined to a small plant group, and is now, after eight 

 years' pursuit, concluded in all essentials. Whether the 

 plan upon which the separate experiments were conducted 

 and carried out was the best suited to attain the desired 

 end is left to the friendly decision of the reader. 



Selection of the Experimental Plants. 



The value and utility of any experiment are determined 

 by the fitness of the material to the purpose for which it is 

 used, and thus in the case before us it cannot be immaterial 

 what plants are subjected to experiment and in what manner 

 such experiments are conducted. 



The selection of the plant group which shall serve for 

 experiments of this kind must be made with all possible 

 care if it be desired to avoid from the outset every risk 

 of questionable results. 



* [It is to the clear conception of these three primary necessities 

 that the whole success of Mendel's work is due. So far as I know this 

 conception was absolutely new in his day.] 



