AN OUTLINE OF MODERN WORK BEARING ON 

 THE THEORY OF DESCENT 



BY J. J. WOLFE 



In my eagerness to select a subject worthy of presentation 

 on this occasion, I have, like many another, attempted a task 

 much bigger than I had realized. It is apparent that nothing 

 approaching encyclopaedic treatment is possible. You will, 

 therefore, find much important work conspicuous by its ab- 

 sence. I do, however, regard the generalizations and experi- 

 ments discussed as being, in the main, those most pertinent 

 to the matter in hand. 



You can hardly be better persuaded than I am, that it 

 is hazardous in the extreme to attempt to speak at the present 

 time with any degree of positiveness concerning the subsid- 

 iary theories involved. Wide differences exist in the minds 

 of equally able students both as to the value and the inter- 

 pretation to be put upon recent and current work. The 

 subject, however, is so vital, and so grips the attention 

 wherever we meet it, that it seems to me well worth while to 

 review this work even if it nuist be in a most tentative 

 fashion. 



Mendel's law 



We may begin this review with the opening of the present 

 century. Until this time the theory of descent was in its 

 essentials just as Darwin had left it in 1859. The year 

 1900, however, is made memorable by the rediscovery of the 

 unpretentious studies of an Austrian monk, Johann Gregor 

 Mendel. His results were published in 1860 in an obscure 

 journal wlierc they lay buried until unearthed independently 

 and almost simultaneously by three distinguished botanists, 

 Dr. Vries of Holland, Tschermak of Austria and Correns of 

 Germany, ^fendel was a student of Carl Nageli, another 

 great botanist, to whom he sent his results, but somehow the 

 master failed to grasp the significance of his old pupil's 

 work. 



