tee ees BRST Y OF CHICAGO ?PRtee 
American Permian Vertebrates. By Samuel Wendell Williston, 
Professor of Paleontology in the University of Chicago. 
152 pages, 39 plates, 8vo, cloth; postpaid $2.68 
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. Especially noteworthy 
are the four nearly complete skeletons of cotylosaurian and 
theromorph reptiles, the most perfect ever discovered in the older 
formation of any country, and of remarkable structure. The 
work is illustrated by the author. 
Contributions to Medical Science by Howard Taylor Ricketts. Pub- 
lished as a Tribute to His Memory by His Colleagues, under the 
Auspices of the Chicago Pathological Society. 
508 pages, 8vo, cloth; net $5.00, domestic postage 33 cents 
Dr. Ricketts died of typhus fever in the City of Mexico, 
May 3,1t910. He wasat that time prosecuting researches into the 
nature of typhus and but a few days before had announced the 
discovery of a micro-organism which is believed to be the cause 
of the disease. He had also shown that the infection may be 
carried by an insect, and thus pointed out the way for preventive 
measures. These achievements, together with earlier work on 
Rocky Mountain spotted fever, give Dr. Ricketts a high and 
honorable place on the records of medical research. 
The present volume contains thirty papers on these and 
allied topics. It is rich in information of immediate value and 
in suggestions to future investigators. It is also an impressive 
memorial to a man whose life was deliberately laid down in the 
service of humanity. 
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