DEC 1 3 192'0 



r 



SCIENCE 



New Series 



Vol. LII, No. 1354 





Fkiday, Dece %^0, 1920 





Single Copies, 15 Cts. 

 AsNUAi, Subscription, $6.00 



NeM^ BlakisU \ Books 



Wilder — Laboratory Manual of i-'i 



With 43 Illustrations. Cloth, ^3.00 Postpaid. 



•opometry 



By Harris W. Wilder, Ph.D., Professor of Zoology, Smith College, 

 Northampton Mass. 



Patten — Early Embryology of the Chick 



With 55 Illustrations, Cloth, ^2.25 Postpaid. 



By Bradley M. Patten, Assistant Professor of Histology and Embryology, 



School of Medicine, Western Reserve University, Cleveland. 



Harman — Laboratory Outlines for Embryology 



2d Revised Edition. Cloth, ;^i.oo Postpaid. 



By Mary T. Harman, Ph.D., Associate Professor of Zoology, Kansas State 

 Agricultural College. 



Cook — Laboratory Experiments In Organic Chemistry 



2d Revised Edition. 8 Illustrations. Cloth, $1.00 Postpaid. 



By E. P. Cook, M.A., Associate Professor of Chemistry, Smith College, 



Northampton, Mass. 



Announcements 



Copaux— Introduction To General Chemistry. An Exposition of the 

 Principles of Modern Chemistry. 30 Illustrations, Nearly Ready. By 

 H. Copaux, (Paris). Translated by HENRY Leffmann, M.D., Member 

 American Chemistry Society. 



Gordon— French-English Medical Dictionary. By ALFRED GOR- 

 DON, M.D., (Paris), Formerly Associate in Mental Disease, Jefferson Medi- 

 cal College. 



Molinari — ^A Treatise On General and Industrial Organic 

 Chemistry. Part I, Volume 2, Cloth, ^8.00. By EttoRE MOLINARI, 

 Milan; Translated by T. H. Pope, F.I.C., (University of Birmingham, 

 England). 



P. Blakiston's Son & Co., Publishers, Philadelphia 



