PREFACE
 

From ancient times heredity has been looked upon
as one of the central problems of biological philoso-
phy. It is true that this interest was largely specu-
lative rather than empiricaL But since MendePs
discovery of the fundamental law of heredity in
1865, or rather since its re-discovery in 1900, a curious
situation has begun to develop. The students of
heredity calling themselves geneticists have begun
to draw away from the traditional fields of zoology
and botany, and have concentrated their attention
on the study of MendePs principles and their later
developments. The results of these investigators
appear largely in special journals. Their terminology
is often regarded by other zoologists as something
barbarous,—outside the ordinary routine of their pro-
fession. The tendency is to regard genetics as a sub-
ject for specialists instead of an all-important theme of
zoology and botany. No doubt this is but a passing
phase; for biologists can little afford to hand over to
a special group of investigators a part of their field
that is and always wiU be of vital import. It would
be as unfortunate for all biologists to remain ignorant
of the modern advances in the study of heredity as
it would be for the geneticists to remain unconcerned
 

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