This book is a review of the physiology of the invertebrates. It is written by one of the Heidelberg group of neo-vitalists and is interesting as showing how the life processes of these animals look from their standpoint. Besides his own observations, the author gives a review of the literature, defining the position of the various writers in reference to his own conceptions. The nervous system is especially considered, and the relation of the animal to its environment is studied in each form. This makes the work especially valuable to psychologists and neurologists.
Vitalistic conceptions are discussed at length, the author believing that some vital force, neither physical nor chemical in nature, is an important factor in every biologic process. The work of biologists in the past is destructively criticized because they did not consider vitalism more and physics and chemistry less.
The book is attractively written, and those who