48 



TRANSACTIONS OF WAGNER 



MENDEL AND HIS LAW 



third of the round seeds produced always round peas, while the other two-thirds 

 produced round and wrinkled in the proportion of three to one. The wrinkled 

 seeds that had come in the second generation always produced only wrinkled 

 seeds. Here comes then the interesting deduction. If two parent peas are 

 one round and one wrinkled, their children will all be round. Their grandchil- 

 dren will be three round to every one wrinkled. Their great-grandchildren will 

 be disposed as follows : The children of one of the round will all be round and 

 will continue in later generations to produce only round peas. Their blood is 

 as purely round as that of their great-grandfather and every trace of their 

 wrinkled grandmother has entirely disappeared. Similarly, the wrinkled 

 grandchildren will produce only wrinkled through generation after generation. 

 In other words, their blood is as wrinkled as that of their wrinkled grandmother 

 and no trace of their round grandfather remains. On the other hand, two of 

 the round grandchildren have in them both the round blood of their round 

 grandfather and the wrinkled blood of their wrinkled grandmother. Each of 

 them will produce offspring of both kinds in proportion of three to one, and of 

 the three, one will be pure and the other two hybrid. If this seems confusing, 

 the following diagram will probably help to make it clear, and the passage 

 should be re-read until the order underlying it is evident, for this is too impor- 

 tant to leave unmastered. 



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Illustration of Mendel's law. 



