SCIENCE 



Fridat, Jantjaet 28, 1916 



CONTENTS 

 The American Association, for the Advance- 

 Ttient of Science: — 



The Isthmus of Panama in its Relation to 

 the Animal Life of North and South Am,er- 

 ica: Professor W. B. Scott 113 



The Needs of Applied Optics: De. P. G. 

 Nutting 124 



Scientific Notes and News 128 



and Educational News 133 



Discussion and Correspondence: — 



Insects in their Relation to the Chestnut- 

 iarlc Disease: F. C. Craighead. Cancer 

 and Sereditjf: Maud Slye. A Mollusk In- 

 jurious to Garden Vegetables: Frank 

 Collins Baker 133 



Scientific BooTcs: — 

 La Science Frangaise: Professor Wm. H. 

 HOBBS 136 



Scientific Journals and Articles 138 



The Poisonous Effects of the Rose Chafer 

 upon ChicTcens: George H. Lamson, Jr. ... 138 



The American Society of Zoologists: Professor 

 Caswell Grave 139 



MBS. intended for publication and books, etc., intended for 

 review should be sent to Professor J. McKeen Cattell, Garrison- 

 on-Hudaon. N. Y. 



THE ISTHMUS OF PANAMA IN ITS 



RELATION TO THE ANIMAL LIFE 



OF NORTH AND SOUTH AMERICAi 



It is a commonplace of geological teach- 

 ing that the past can be understood only- 

 through a knowledge of the present and it 

 is equally true that the present can be 

 fully comprehended only through a knowl- 

 edge of the past. Each must be employed 

 to elucidate the other and we must pass 

 from one to the other, as new discoveries 

 are made in either realm. 



The problems which deal with the ex- 

 isting geographical distribution of animals 

 have received much light from the prog- 

 ress of paleontological discovery and the 

 present arrangement is clearly seen to be 

 the necessary outcome of an illimitable 

 series of past changes, climatic, geo- 

 graphical and biological. Even in pre- 

 Darwinian days the geographical distribu- 

 tion of animals had been given much atten- 

 tion, as a collection of interesting facts, 

 though, under the belief in special creation 

 then prevailing, no explanation of those 

 facts was possible. The general adoption 

 of Darwin's views immediately placed the 

 subject in a new light, for it was at once 

 seen that, unless the theory of evolution 

 could offer a rational and satisfactory solu- 

 tion of these problems of distribution, the 

 foundations of the theory would be greatly 

 weakened. 



No result of paleontological studies 

 has, of late years, been more striking than 

 the clear recognition of the fact that migra- 



1 Lecture before tlie American Association for 

 the Advancement of Science at its San Francisco 

 meeting, August, 1915. 



