tgit] CURRENT LITERATURE 235 
A third series is the A ppleton’s Scientific Primers, edited by J. REYNoLDS 
GREEN, an English botanist. Three of this series have appeared, the third 
by the editor and entitled Botany. It is written from the English point of 
view, which lays much stress on details and terminology, but is effective in 
ieedentiag the plant as a living organism, for the author is a physiologist. 
A great deal of material is packed in the 128 pages, and it would be interesting 
to know the impression such material makes upon those without laboratory 
experience.—J. M. C 
Mendelism 
PuNNET?’s little book? on Mendelism, which was one of the first attempts 
at a simple popular presentation of its subject, has been completely rewritten 
and enlarged for its third edition. It is in fact a new book, written however 
from the same point of view and for the same circle of readers. The author 
limits himself to the presentation of illustrative examples, with no attempt 
at exhaustiveness in any phase of the subject, referring readers to BATESON’S 
book on Mendel’s principles of heredity for more detailed information and for 
references to the literature. The material used to illustrate the various 
principles is well chosen, and is mostly derived, as might be expected, from 
the work of the Cambridge group of geneticists, of which the author is one. 
This results in a decided advantage, since the author’s familiarity with his 
material favors clarity and vividness of presentation. The slight sense of 
provincialism given by this method is in this way more than compensated for. 
While the treatment is in the main admirable, several unfortunate errors 
have crept in. It is stated (p. 2) that “among animals the female contributes 
the ovum and the male the spermatozoon; among plants the corresponding 
cells are the ovules and pollen grains.” . Several other zoological writers on 
genetic subjects have obviously made the same mistake. The animal ovum 
(after maturation) and spermatozoon are homologous cells, but ovules and 
pollen grains are not single cells, and not even homologous structures, the 
ovule consisting mostly of maternal somatic tissue, and the pollen grain being 
a much reduced gametophyte. The embryo sac within the ovule, and the 
sperm nuclei in the pollen tube, approximately correspond to the ovum and 
spermatozoa. On page 51, line 16, c should be C, and in fig. 8 on the following 
page the three squares which are black should be albino, and the three mark 
“albino,” but containing C, should be black. The author assumes that 
dominance of a character always indicates that such character is due to some- 
thing added to the recessive form, thus ignoring the possibility pointed out 
several years ago by the reviewer that the positive character may be reces- 
*Punnetr, R, C., Mendelism. Third edition, entirely rewritten and much_ 
enlarged. at mee 192. pls. 6 and frontispiece. figs. 32. New York: The Mac- 
millan Co. 
3The “presence and absence” hypothesis. Amer. Nat. 43:410-419. 1909. 
