First published in 1939 second impression in 1950, this book provides an account of the changes in, and main principles of, genetics at that time. These are illustrated by references to the most authoritative and then recent investigations. Special attention is paid to the way in which genetics overlaps with other fields of inquiry, since it is often in these border-line subjects that the most important advances are to be expected.

First published in 1935 this edition in 1946, this short account of the science of embryology was the first book in English to provide a simple outline of the whole of this important subject. The study of development is perhaps the best method of approach to the most fundamental of all biological problems, the problem of how all the diverse activities are integrated so as to make up a complete individual organism. This volume is simply written in order to enable the general reader to understand the revolutionary advances made in the subject at that time.