CURRENT LITERATURE 
BOOK REVIEWS 
Heredity 
Several courses of public lectures on heredity have been made the basis 
of a very readable book by CAsTLe,' in which the principles of Mendelian 
heredity and other related topics are discussed with special reference to their 
bearing upon evolution and animal breeding. The rapidly increasing number of 
to have the subject presented in easily comprehensible language by one who is 
among the foremost investigators of the phenomena with which the book 
deals. The manner of origin of this book makes it ane that the author 
should illustrate the various principles of heredity by examples from his own 
extensive experiments, whenever such examples are available, and this method 
gives the book a unique value. 
he brief introductory chapter on ‘“‘Genetics a new science’’ recognizes 
the profound influence exercised by the theory of evolution in many fields of 
human activity, and shows how the evolutionary idea has forced man to con- 
sider his own probable future and to seek to control that future. As the 
“existence of civilized man rests ultimately on his ability to produce from the 
earth in sufficient abundance cultivated plants and domesticated animals,” 
to the conditions of present-day agriculture,” and especially to an exposi- 
tion of the ‘“‘operations” of Mendel’s law of heredity, the author specifically 
addresses himself. 
hap. i on “the duality of inheritance” defines heredity as “organic 
resemblance based on descent,’’ and discusses fertilization, pointing out that 
either eggs or sperms can Giles certain experimental conditions produce a 
complete organism without union with another gamete, and that such a result 
is realized regularly in nature in the case of male bees and wasps. The x and 
2x generations of Lotsy are then considered under ha designation V and 2V 
generations, a change of t Spa: which has nothing to ——- it. 
Chap. ii distinguishes between “germ-plasm” and the body or “soma,” and 
cites experiments in the transplantation of eggs to an alien soma as proof of 
™ Caste, W. E., Heredity in relation to evolution and animal breeding. 8vo, 
pp. xii+184. figs. 53. New York: D. Appleton & Co, tort. 
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