DYNAMIC EVOLUTION 



Redfield's Theory of Inheritance of Results of Training and Use Not Supported 

 by Adequate Biological Evidence. 



A Review by Raymond Pearl 

 Biologist, Agricultural Experiment Station, Orono, Maine 



THAT "dynamic" should appear 

 as an integral part of the 

 title of a book by Mr. Rcdficld 

 is altogether appropriate. ^ As a 

 writer he is nothing if not forceful. He 

 has (by right of training and experience) 

 all of the good lawyer's skill in carrying 

 the reader deftly across weak places in 

 the logic of the argument or over 

 lacunae in the factual basis, by means 

 of a flow of vigorous and sometimes 

 brilliant rhetoric. His writings have 

 been followed with great interest by 

 the present reviewer for ten years or 

 more past. The occasion of that inter- 

 est, however, has not been primarily 

 genetics, but rather the psychology of 

 scientific paradoxy. De Morgan's most 

 delightful "Budget of Paradoxes" dealt 

 with those ancient and honorable para- 

 d oxers who squared the circle, made 

 machines calculated perpetuall}^ to 

 move, and engaged in similar activities. 

 In his day the biological paradoxer had 

 not yet appeared in numbers, and the 

 genetic paradoxer was totally absent. 

 It would have delighted De Morgan 

 beyond measure to have dissected 

 Mr. Redfield's biology and through 

 the maze of specious verbiage shown, 

 at point after point, where that author's 

 methods of scientific reasoning and jjroof 

 deviated from those of his more orthodox 

 colleagues. 



As a scientific investigator Mr. Red- 

 field labors under at least one very 

 serious handicap. It is that he is 

 firmly committed to a thesis in advance 

 of the investigation. This assertion 

 he would no doul)t deny vigorously. I 

 am entirely willing to rest my case as 

 to its validity on the sum total of Mr. 



Redfield's writings on heredity and 

 related topics. 



It would be difficult to state liriefly 

 this thesis in terms which would be 

 entirely acceptable (I fear) to its 

 author. I shall therefore merely try 

 to state my understanding of it in 

 ordinary terminology. It is essentially 

 this: that as any organ of the body, 

 or the body as a whole, or the mind, 

 is used or exercised there results, in 

 some manner not made clear physio- 

 logically, an accumulation or storage of 

 energy in the germ cells with respect 

 to the organ or function exercised. 

 This accumulation of cnerg}- (with 

 respect to a particular character) is 

 then supposed to be transmitted to the 

 next generation, again by some process 

 not made clear physiologically, but 

 according to definite rules. These rules 

 of transmission, while alwa\'s definite, 

 have been \-ariously and sometimes 

 curiously modified in the course of 

 Mr. Redfield's writings upon the sub- 

 ject. The practical moral for the 

 breeder, however, is in general, that in 

 breeding for performance of an\- sort 

 it is wise to use as breeders individuals 

 which have been "developed" and 

 hence have stored energy. Further, 

 this will in general mean (though Mr. 

 Redfield's latest codification of the 

 rules of energy transmission by sex, etc., 

 etc., makes a ])erfectly general statement 

 of his prece]jts im])()ssible in few words) 

 that the ])arents of great ])erfonTiers 

 are likely to be found amongst relatively 

 aged animals. 



The ])re.sent book is essentially a 

 condensed epitome of the author's 

 earlier writings upon this subject which 



1 Dynamic Evolution. A Study of the Causes of Evolution and Dcgcneracv. Bv Casper L. 

 Rcdficld. New York rin<! Lon.lon iC. \\ I'utnam's Sons), 1<)14. P])- -^K'. I'ricc Sl.-'^O net. 



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