326 THE POPULAR SCIENCE MONTHLY 



heredity and at the same time brought to light a long neglected and 

 forgotten work on " Experiments in Plant Hybridization " by Gregor 

 Mendel, in which this same principle was set forth in detail. This 

 principle is now generally known as " Mendel's Law." Mendel, who was 

 a monk and later abbot of the KonigsMoster, an Augustinian monastery 

 in Briinn, Austria, published the results of his experiments on hybridi- 

 zation in the Proceedings of the Natural History Society of Briinn in 

 1866. The paper attracted but little attention at the time although it 

 contained some of the most important discoveries regarding inheritance 

 which had ever been made, and it remained buried and practically un- 

 known for thirty-five years. Plant hybridization had been studied ex- 

 tensively before Mendel began his work, but he carried on his observa- 

 tions of the hybrids and of their progeny for a longer time and with 

 greater analytical ability than any previous investigator had done. The 

 methods and results of his work are so well known through the writings 

 of Bateson, Punnett and many others, that it is unnecessary to dwell at 

 length upon them here. In brief Mendel's method consisted in crossing 

 two forms having distinct characters, and then in counting the number 

 of offspring in successive generations showing one or the other of these 

 characters. 



During the eight years preceding the publication of his paper in 

 1866 Mendel hybridized some twenty-two varieties of garden peas. 

 This group of plants was chosen because the different varieties could be 

 cross-fertilized or self-fertilized and were easily protected from the in- 

 fluence of foreign pollen; because the hybrids and their offspring re- 

 mained fertile through successive generations ; and because the different 

 varieties are distinguished by constant differentiating characters. Men- 

 del devoted his attention to seven of these characters, which he fol- 

 lowed through several generations of hybrids, viz., 



(1) Differences in the form of the ripe seeds, whether round or 

 wrinkled. 



(2) Differences in the color of the food material within the seeds, 

 whether pale yellow, orange or green. 



(3) Differences in the color of the seed coats (and in some cases of 

 the flowers also), whether white, gray, gray brown, leather brown, with 

 or without violet spots. 



(4) Differences in the form of the ripe pods, whether simply in- 

 flated or constricted between the seeds. 



(5) Differences in the color of the unripe pods whether light to 

 dark green, or vividly yellow. 



(6) Differences in the positions of the flowers, whether axial, that is 

 distributed along the stem, or terminal, that is bunched at the top of 

 the stem. 



(7) Differences in the length of the stem, whether tall or short. 



