MENDEL’S PRINCIPLES OF HEREDITY 
58 
the Natural History Society of Brunn in 1865, remained un- 
known to the present day. It is impossible to imagine where 
we should have been to-day in our knowledge of heredity had 
Darwin only known of Mendel’s work. . . . The point for us is 
that while there may be variation in the Darwinian sense there are 
also sudden changes where animals of different characters are 
bred together, and under certain circumstances these changes 
are inherited. Mendel’s theory explains both the changes and 
their inheritance ’ (Wilson). 
The scientific world had to wait until the dawn of the 
twentieth century before it heard of Mendel’s law. Since then 
much original confirmatory work has been recorded, but much 
remains to be done. 
In approaching the study of heredity it is absolutely neces- 
sary to have a preliminary knowledge of botany, especially of 
the physiology of plant life. I would suggest Percival’s 
* Agricultural Botany ’ as a work for the study of any intending 
student. The scheme of this book carries one on by means of 
a charming series of simple experiments, which impress each 
fact upon the memory. My motto is ‘ Take care of the facts, 
the names will take care of themselves,’ but sooner or later the 
terminology must be mastered, or one would be in the position 
of possessing a dispensary full of valuable drugs all without 
labels ! I would suggest, in all humility, that a definite system 
of reading be carried out. One should have an indexed note- 
book in which to enter up and define every unfamiliar word, and 
never to pass a word without looking up the meaning when 
in doubt. Also a note-book for each work studied in which 
to enter up short notes of every paragraph ; otherwise one is 
led away by the beauty of the style to read more than can be 
duly assimilated. Given a general knowledge of Darwin’s 
works, a preliminary study of Romanes’ ‘ Darwin and after 
Darwin ’ will be found of great utility. One is then in a 
position to study the whole question brought right up to date 
by Bateson’s monumental work. 
Mendel’s papers are well described by Bateson as * models 
of lucidity and expository skill. His success is due to the 
clearness with which he thought out the problem.’ 
Mendel laid it down as essential to start with pure-breeding 
