University of Chicago Press 
THE MECHANISTIC CONCEPTION OF LIFE. Biological 
Essays. By Jacques Loeb, Head of the Department of Experi- 
mental Biology, Rockefeller Institute for Medical Research. 
238 pages, 12mo, cloth; 6s. net. 
The achievements of Professor Jacques Loeb in the field of experimental 
biology have made him so widely known as to insure any book of his a large circle 
of readers. His experimental work at the Universities of Chicago and California, 
as well as in his present position, gives this volume an especial significance. 
In this his latest work Professor Loeb presents many of the current problems 
in biology, and discusses the question whether the phenomena of life can be 
explained by physical and chemical laws. He finds it possible to control by 
physical or chemical means not merely the processes of reproduction, but also the 
conduct of animals with reference to environment. 
The New York Medical Journal. — " The profession, as welL as everyone interested in biology, 
will thank the author and the publishers for collecting these essays and placing them before the 
reading public." 
Johns Hopkins Hospital Bulletin. — "All eager to know more of the origin of life will find no 
modern book of its size nearly so instructive or inspiring." 
AMERICAN PERMIAN VERTEBRATES. By Samuel Wen- 
dell Willlston, Professor of Paleontology in the University of 
Chicago. 
152 pages, 39 plates, 8vo, cloth ; 105. net. 
This work comprises a series of monographic studies with briefer notes and 
descriptions of new or little-known amphibians and reptiles from the Permian 
deposits of Texas and New Mexico. The material upon which these studies are 
based was for the most part collected during recent years by field parties from the 
University of Chicago. The book is offered as a contribution to knowledge on the 
subject of ancient reptiles and amphibians, with such summaries and definitions — 
based chiefly on American forms — as our present knowledge permits. The work 
is illustrated by the author. 
Athenaeum. — "The paleontologist will welcome the work as a solid contribution to our 
knowledge of a fauna which is of exceptional interest to the student of evolution, inasmuch as it 
includes forms that help to bridge over some of the differences between reptiles and am- 
phibians." 
The publications of the University of Chicago Press, a full catalogue of which will 
be sent on application, are sold in the United Kingdom and the British Colonies by 
THE CAMBRIDGE UNIVERSITY PRESS, Fetter Lane, London, EX. 
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