OUTSTANDING BIOLOGICAL ADVANCES 41 



covered by the botanists De Vries, Torrens, and 

 Tschermak. By searching the literature for anticipa- 

 tions of their results, the unrecognized papers of 

 Mendel were brought to light and made generally 

 known to the scientific world. 



Since 1900, extensive experiments by Bateson and 

 many others have served to confirm and extend 

 Mendel's discovery. In the United States the experi- 

 ments of Davenport and of Castle on inheritance in 

 poultry, the inheritance of fur in guinea-pigs, erect- 

 ness of ears of rabbits, etc., the far-reaching experi- 

 ments of Morgan with the fruit-fly, as well as the 

 experimental work of others, have extended our 

 knowledge of Mendelian inheritance. The combined 

 work on inheritance in animals and plants of all 

 observers has so thoroughly supported Mendel's 

 conclusions, that the principle of alternative in- 

 heritance is commonly spoken of as Mendel's law. 1 



Other investigations have led to the recognition of 

 the physical basis of heredity and to the idea of 

 germinal continuity. Within the nucleus of cells of 

 plants and animals there are certain very minute 

 bodies, the chromosomes (discovered 1883), which 



1 The seven paragraphs above are quoted from the writer's Biology and 

 Its Makers. 



