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J? 

 loe Libra; 



SCIENCE 



Friday, June 25, 1920 



CONTENTS 



Irreversible Differentiation and Orthogenesis: 

 Pkofessoe C. Judson Herrick 621 



Educational Institutions represented in the 

 Mellon Institute : W. A. Hamoe 625 



Scientifio Events: — 



The Cardiff Meeting of the British Asso- 

 ciation; The English Deep-sea Fisheries ; The 

 Sixth Exposition of Chemical Industries; 

 The Work of the National Committee on 

 MathematicaZ Requirements; The Elliot 

 Medal in Zoology and Paleontology 627 



Scientific Notes and News 630 



University and Educational News 633 



Discussion and Correspondence: — 



The Use of the Term Fossil: Peofessoe 

 EiCHAED M. Field. TJie Fixation of At- 

 mospheric Nitrogen: De. Chaeles A. 

 DOEEMUS 634 



Current Research and Fublication in the Amer- 

 ican Museum of Natural History: De. 

 Henry FAiEriELD Osboen 636 



Notes on Meteorology and Climatology: — 

 The Effect of Snow upon the Growth of 

 Winter Wheat : C. LeEoy Meisingee 639 



Special Articles: — 



Transference of Nematodes from Place to 

 Place for Economic Purposes: De. N. A. 

 Cobb. The Interaction of Ethylene and 

 Sulphuryl Chloride: William Foster .... 640 



The American Philosophical Society: Pro- 

 fessor Arthur W. Goodspebd 642 



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

 teviev should be sent to The Editor of Science, Ganison-on- 

 Hudson, N. Y. 



IRREVERSIBLE DIFFERENTIATION 

 AND ORTHOGENESIS 



The publication in 1919 of the three noble 

 volumes of posthumous works of the late 

 Professor Whitman^ redirects our attention 

 to the problem of orthogenetic evolution. 

 The evidence here presented may be regarded 

 as demonstrative that in pigeons variations 

 do not occur in all cases at random around 

 fixed modes as unit characters in accordance 

 with the laws of probability, but that they 

 tend to appear in the course of phylogeny in 

 an irreversible series. 



Numerous other students of evolution have 

 formulated similar conceptions under the 

 names, orthogenesis, orthoplasy, directive evo- 

 lution, etc., some of which are referred to by 

 Whitman, and others are cited at length by 

 Baldwin in his book on " Development and 

 Evolution" (New York, 1902). Most of 

 these statements leave much to be desired 

 from the scientific standpoint and they fre- 

 quently lead to the expressed or implied 

 postulation of metaphysical factors.^ Nageli's 

 principle of perfection is of this sort and has 

 not been especially fruitful. Others, like 

 Eimer,' though basing their conclusions on 

 extensive critical observation, have allowed 

 themselves to be swept along by controversial 



1 ' ' Orthogenetic Evolution in Pigeons. ' ' Post- 

 humous "Works of Charles Otis Whitman. Edited 

 by Oscar Riddle. Published by the Carnegie In- 

 stitution of Washington, 1919. 



2 The term orthogenesis has been applied in a 

 great variety of seiiBes, some of them decidedly 

 mystical. These are summarized by Vernon L. 

 Kellogg in "Darwinism To-day," New York, 1907, 

 pp. 274-288. 



3 Eimer 's Leyden address published by The 

 Open Court Publishing Co., Chicago, 1898, under 

 the title, "On Orthogenesis and the Impotence of 

 Natural Selection in Species-Formation," gives a 

 summary of his views with citation of the original 

 sources of his data. 



