MENDELISM 43 



of which cannot be overestimated in connection with 

 the history of the evolution of organic forms." 



Although Mendel modestly implied that any one who 

 might survey the past work would arrive at the convic- 

 tion mentioned, it was in fact due to his quite excep- 

 tional and extraordinary insight that he was able to put 

 his ringer on the weak point in previous investigations, 

 and plan others according to "the only right way" to 

 resolve the difficulties and uncertainties surrounding the 

 subject. We have here a beautiful example of the 

 scientific method, - - not working at random, but fol- 

 lowing a carefully thought-out plan, developed after a 

 full consideration of what was previously known. 



3. In order to carry out the experiments planned, it study of 

 was necessary to choose varieties of peas which differed characters 

 in some marked characters, and cross one with another. inpas 

 Thus the ripe peas may be either smooth (or with only 

 shallow depressions) or angular and wrinkled ; they may 



be green or various shades of yellow. The oods may be 

 deeply constricted between the seeds, or lack this char- 

 acter. The stem may be short or long. These and 

 other characters were readily observed, and it was noted 

 that they represented opposites, as smooth or wrinkled, 

 green or yellow, tall or short, etc. Mendel now crossed 

 plants having such opposite characters, and watched 

 the inheritance of these particular characters, not es- 

 pecially concerning himself with the other parts or 

 peculiarities of the plants. 



4. At the outset Mendel noticed that the offspring Dominant 



of his crosses were not intermediate between the parents. r " es " 



crosses 



car _ 



On the contrary, in respect to the characters studied, acters in 

 they closely resembled one or the other parent. Of 

 each pair of opposing characters, one appeared in the 

 offspring, the other being absent. Not only this, but 



