SCIENCE 



Friday, March 24, 1916 



CONTENTS 



The Advancing PendiUum of Biological 

 Thought: Professor C. C. Nutting 403 



The Natural Charges of Metals: Professor 

 Fernando Sanfokd 409 



The Fire and the Museum at Ottawa: Harlan 

 I. Smith 415 



Sobert James Davidson: Dr. Frank K. Cam- 

 eron 418 



The RocTcefeller Foundation and the General 

 Education Board 419 



Centennial of the Coast and Geodetic Survey. . 420 



Scientific Notes and News 422 



University and Educational News 425 



Discussion and Correspondence: — 



Mesozoic Pathology and Bacteriology: Dr. 

 EOY L. MooDiE. Efficient Summer Vaca- 

 ticms: Dr. Lancaster D. Burling. German 

 Geologists and the War: Walter L. Bar- 

 rows 425 



Scientific BooTcs: — ■ 

 Davenport's The Feebly Inhibited: Pro- 

 fessor Edward L. Thobndike. Publica- 

 tions of the Nutrition Laboratory of the 

 Carnegie Institution: Professor Yandell 

 Henderson. Herrick's Introduction to 

 Neurology: Dr. P. G. Stiles 427 



Special Articles: — 



The Botanical Identity of Lignum nephriti- 

 cum: Dr. W. E. Safford. Preliminary Stud- 

 ies on Heated Soils: James Johnson. The 

 Interferences of Parallel and Crossed Bays: 

 Professor Carl Barus 432 



Societies and Academies : — 



The Botanical Society of Washington: Dr. 

 W. E. Safford. The Biological Society of 

 Washington: Dr. M. W. Lyon, Jr 436 



MSS. intended for pablicatien and books, etc., intended for 

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

 •n-Hudaon. N. Y. 



THE ADVANCING PENDULUM OF BIO- 

 LOGICAL THOUGHT 



The specialist often finds it interesting, 

 and sometimes profitable, to pause in the 

 intensive pursuit of his own little field and 

 take time to contemplate the general trend 

 of thought in biological science. 



In my own case it is often borne in upon 

 me that the zoological public is little in- 

 terested in the group of animals, the Hy- 

 droida, with which I work, and it is a posi- 

 tive relief to contemplate the broader as- 

 pects of the field of natural science. 



Let this, then, be my excuse for present- 

 ing a paper that is non-technical in form 

 and more of the nature of a general survey 

 of the path along which we have traveled 

 in the acquisition of general biological 

 truth. 



Upon taking such a survey it at once be- 

 comes evident that progress has been made 

 along a sharply zigzag road, with succes- 

 sive swings to right and left, involving 

 abrupt changes of accepted theories. In 

 fact this path is that which would be traced 

 by a pendulograph as made by an advanc- 

 ing pendulum. The actual movements 

 would be mainly to the right and left of a 

 median line representing actual progress, 

 but each swing of the pendulum would 

 make a slight but sure advance along that 

 median line. 



The idea is not really new and has been 

 incidentally touched upon by various 

 writers ; but it seems to me that it would be 

 profitable to consider with some care a few 

 of the comparatively recent swings of the 

 pendulum, to note the advance made by 

 each, and possibly to arrive at some general 



