22 THE NEXT GENERATION 



7. The height of the plant. One kind had a stem seven 

 feet long, while the stem of another was but a foot long. 



Mendel kept each kind absolutely separate from all the 

 others ; that is, he never let the pollen of one kind reach 

 the stamens of another kind unless he himself put it there. 



By being so careful he knew precisely which parents 

 headed the list of each set of descendants. He could also 

 tell which characters crowded the others out in the next 

 generation. Tho.se that dominated he called dominant; 

 those that receded out of sight he called recessive. In fact, 

 Mendel was the first man who ever used these words in this 

 way, but they explain the case so well that nowadays we all 

 use them. Here are some of the dominant and recessive 

 characters of Mendel's peas in two separate columns. 



DOMINANT RECESSIVE 



Tallness. Dwarfness. 



Round seeds. Wrinkled seeds. 



Colored seed coats. White seed coats. 



Yellow albumen in cotyledon. Green albumen in cotyledon. 



Purple flowers. White flowers. 



Sometimes characters were neither dominant nor recessive, 

 so that the next generation was of necessity a mixture. 



Mendel kept on with his work of crossing pollen, watching 

 results, and writing records until eight full years had passed. 

 Then at last, in 1865 and again in 1869, he reviewed what 

 he had done, put his statistics together, came to his conclu- 

 sions, and wrote them down for the benefit of other people. 

 In these papers he told how he had developed new kinds of 

 peas, why he had done it, and what laws of inheritance he 

 believed he had discovered. 



When he read his papers to the scientific society at Briinn, 

 he himself was excited and enthusiastic, but he saw plainly 



