vi MENDELISM 



Principles of Heredity (Cambridge, 1 909), where a full 

 account of these matters is readily accessible. Neither 

 have I alluded to recent cytological work in so far as it 

 may bear upon our problems. Many of the facts con- 

 nected with the division of the chromosomes are striking 

 and suggestive, but while so much difference of opinion 

 exists as to their interpretation they are hardly suited 

 for popular treatment. 



In choosing typical examples to illustrate the growth 

 of our ideas it was natural that I should give the prefer- 

 ence to those with which I was most familiar. For this 

 reason the book is in some measure a record of the work 

 accomplished by the Cambridge School of Genetics, and 

 it is not unfair to say that under the leadership of 

 William Bateson the contributions of this school have 

 been second to none. But it should not be forgotten 

 that workers in other European countries, and especially 

 in America, have amassed a large and valuable body of 

 evidence with which it is impossible to deal in a small 

 volume of this scope. 



It is not long since the English language was enriched 

 by two new words — Eugenics and Genetics — and their 

 similarity of origin has sometimes led to confusion be- 

 tween them on the part of those who are innocent of 

 Greek. Genetics is the term applied to the experi- 

 mental study of heredity and variation in animals and 

 plants, and the main concern of its students is the 

 estabUshing of law and order among the phenomena 



