1918] CURRENT LITERATURE 277 
these are sufficient to show that Lorp’s interpretations throw no light on the 
pro " 
Chapter VIII, ‘Determination of sex, secondary sexual characters, and 
sexual instincts,” deals first with the cytological basis of sex-determination. 
Loes accepts in their most extreme form the conclusions of the cytologists 
concerning the “‘sex-chromosomes,”’ and mys that ‘thus far ” the facts Rare 
with the dominating influence of certai 
Actually, however, these facts, assuming that they are all facts, have been inter- 
preted very differently by different authors. Sex-determination in plants is 
mentioned in only two brief sentences. The discussion of the physiological 
basis of sex-determination is largely concerned with sex-hormones, experi- 
mental and parasitic castration, and the influence of nutrition on sex. The 
intersexual forms of the moth Lymantiria obtained by GoLpscHMIDT are 
described, but without comment. 
The account of “Mendelian heredity and its mechanism” in chapter IX 
begins with a brief outline of Mendelian theory and of Morcan’s hypothesis 
of localization of the Mendelian factors in the chromosome, concluding with 
the statement “biology has thus reached in the chromosome theory of Mende- 
lian heredity an atomistic conception, according to which independent material 
out of this kaleidoscopic assortment ?”” The answer is that the egg cytoplasm 
is the embryo in the rough, it that each determiner in the chromosomes 
Sives rise to one or more substances which influence various parts of the body. 
But when we ask how the egg cytoplasm comes to be the embryo, and in the 
rough, and how it happens that the substances produced are adjusted to the 
different regions of the cytoplasm, we find no answer except the assertion that 
evolution can produce harmonious organisms, because those that are not 
harmonious are eliminated. 
apter X on “Animal instincts and tropisms” adds nothing essential 
to LoEB’s previous discussion of the subject, and is open to the same criticisms. 
The chapter is devoted largely to the consideration of reactions to light and 
the attempt to show that they are in accord with the Bunsen-Roscoe law of 
Photochemical reactions, according to which the chemical effect is within 
certain limits equal to the product of intensity into duration of illumination. 
There is but little discussion of fact or theory which does not agree with LoEB’s 
conclusions. As regards the trial and error theory, LorB says that it has been 
refuted by practically all workers in the field. Students of animal behavior 
will be interested to discover that the question has been settled. 
“The influence of environment,” chapter XI, is devoted largely to con- 
sideration of the influence of temperature, the temperature coefficient of 
Physiological processes, salt antagonisms, and balanced solutions. This is 
followed by a chapter on “Adaptation to environment,” which is somewhat 
less extreme than some of the author’s earlier discussions of the subject, but 
