HEREDITY 



INTRODUCTION 



AMONGST many other problems of heredity, Professor 

 Pearson and his pupils have investigated the inheritance 

 of stature in man. They proceeded by measuring, in a 

 great many instances, the height of a father and one or 

 more of his sons. The average height of all the men 

 measured was about five feet eight inches. It was 

 found that if one considered by itself the group of 

 fathers measuring about six feet, the average height of 

 their sons was about five feet ten. Further, if one took 

 by itself the group of fathers measuring five feet six, 

 the average height of their sons was about five feet 

 seven. That is, tall or short fathers tended to have tall 

 or short sons respectively, but the resemblance as regards 

 stature was only partial. In other words, variations in 

 stature were inherited, but only to a limited extent. 



Professor Johannsen of Copenhagen has carried out 

 an investigation on similar lines with regard to the 

 size of the seed in beans. Taking the seeds from a 

 single plant, he separated the large from the small, and 

 planted each lot separately. From the resulting plants, 

 when ripe, he took the seeds and weighed them ; he 

 found no difference in the average size of the seed in 

 the two lots. He repeated this experiment several 

 times, and kept on selecting for several generations, 

 but always with the same result. Variations in the 

 size of seed, within a single race, were not inherited 

 at all. 



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