62 BOTANICAL GAZETTE [yULY 
is a curious blindness to other facts of heredity which leads the author to the 
opinion that Mendelism probably represents the only type of inheritance which 
exists. Because characters sometimes behave as units does not exclude the occur- 
rence of several other types of hereditary behavior, nor does the recognition of this 
fact belittle the facts of Mendelism. In the comparison of Gatron’s law of 
ancestral inheritance with the Mendelian ratios, the fact that GALTON’s law was 
designed for populations rather than for individuals seems to have been over | 
ooked. 
The method by which the process of segregation is visualized is very well 
exemplified in the following quotation (p. 56): 
-Henceforth we have to penetrate behind the visible appearance of the individual, . 
and endeavor to reconstruct first those processes of cell division which produced the 
germ-cells or gametes, distributing the characters or factors among them according 1 . 
definite systems; and then the subsequent process of union of those gametes, pair by 
ment those properties of structure, instinct, and conduct conferred upon it by that 
particular complement of factors which its two original gametes contained. 
Yet, fascinating as the theory appears, it must be remembered that it still remails 
an unproven hypothesis, to explain a characteristic method of hereditary behavior. 
The hypothesis has certainly proved useful, even though another explanation af 
the phenomena of segregation may ultimately be found necessary. 
The book is attractively printed on a good quality of smooth paper, and appea® 
to be exceptionally free from typographical errors. Its attractiveness is enhanced 
by three photographs of MENDEL and several colored plates, together with numer 
ous illustrations and diagrams. A bibliography, and subject and author indices 
are found at the end of the volume. The work will be indispensable for referen® 
by all students of heredity as a compendium of Mendelian phenomena. 
A small volume entitled Mendelism, by R. C. PUNNETT, a collaborator with 
BATESON, was published in 1905 and passed through a second edition. 
American edition? has just appeared, with a preface by GAYLORD WILSHIRE. I 
is a simple, clear account of Mendelian phenomena, and as such has doubtless 
done much to popularize Mendelism among general readers. The new edition 
also contains reprints of an article on ‘“‘Applied heredity,” which appeared ~ 
Harper’s Monthly Magazine, and an article subtitled ‘‘Old Bottles,” reprinted 
from The New Quarterly, which is. chiefly a criticism of THomson’s volume = 
Heredity,3 of the position taken by WALLACE and Poutton, and the attempt 
minimize the importance of non-Mendelian types of inheritance. The paper 5 
poor and the diagrams coarse, but the little book will doubtless serve its P OF 
as a cheap and popular presentation of Mendelism.—R. R. GATES. 
2 PUNNETT, R. C., Mendelism. r2mo. pp. 109. New York: Wilshire Book 
Company, 200 William St. 1909. 50 cents. _ & 
3 THomson, J. ARTHUR, Heredity. London. 1908. 
