March 24, 1916] 



SCIENCE 



405 



agenesis, kinetogenesis, physiogenesis, bath- 

 mogenesis and mnemogenesis. 



The advance made by this Neo-Lamarck- 

 ian swing of the pendulum was not so great 

 nor so sure as its immediate predecessor. 

 The battle in the main went against the 

 Neo-Lamarckians. But they were a no- 

 table company, embracing many of the 

 foremost names in the biological roster of 

 that time. Such names as Hyatt, Cope, 

 Dall, H. F. Osborn, Packard, Riley, Eigen- 

 mann and many others are significant of 

 the standing of that notable group. 



But there was some advance made by the 

 Neo-Lamarckian swing. Cope's "law of 

 the unspecialized" was a direct contribu- 

 tion to our understanding of the course, if 

 not the cause, of organic evolution in its 

 broader aspects; and Eigenmann's argu- 

 ment for the inheritance of acquired char- 

 acters drawn from his masterly studies of 

 blind vertebrates has not, so far as I am 

 aware, been successfully controverted. To 

 this day a very respectable body of zoolo- 

 gists are inclined to feel, deep down in 

 their consciousness, that, as Geddes and 

 Thomson say: 



It is idle to say that what living creatures do or 

 fail to do has no racial importanee.i 



The remaining swing of the pendulum 

 that demands our attention has just reached 

 its maximum, and may well be designated 

 as the "Mendelian swing." Not entirely 

 Mendelian, either, but partly de Vriesian. 

 This was in a direction tending to a wide 

 departure from the position that had been 

 taken by practically all workers since Dar- 

 win ; i. e., that natural selection had worked 

 mainly, if not exclusively, by the gradual 

 summation of small but appreciable indi- 

 vidual variations. De Vries, with his 

 famous evening primrose, had demon- 

 strated, to his own satisfaction at least, 

 that species arise by sudden mutations and 



1 "Evolution," 1911, p. 201. 



thus sprung full-orbed into being and that 

 ordinary variations never produced spe- 

 cies by their summation. He claimed, how- 

 ever, that his theory was a direct contribu- 

 tion to Darwin's theory of natural selec- 

 tion. 



At about the same time that de Vries 

 was working with his primroses, the Aus- 

 trian monk, Mendel, was working with 

 sweet peas and made discoveries whose im- 

 portance was not recognized until, in 1900, 

 his results were verified by de Vries, Bate- 

 son and others in Europe and Castle, 

 Davenport and others (a little later) in 

 America. This was another epochal event 

 in biological advance, and the scientific 

 world was soon plunged into a warm dis- 

 cussion of the "Mendelian Law." Domi- 

 nant and recessive, segregation, homozy- 

 gotes and heterozygotes, determiners and 

 factors, genotypes and phenotypes, were 

 the order of the day. But worse was still to 

 come. Factors of four kinds, determiners 

 of three kinds, potencies of three kinds; 

 then inhibitors to explain why the thing 

 did not work. Allelomorphs, sex-limited 

 inheritance and side chains, sweet peas and 

 white mice, guinea-pigs and chickens, filled 

 the cireumambiant atmosphere. Biological 

 laymen endeavored to steady their whirl- 

 ing brains while filled with admiration for 

 the warm imagination of these new proph- 

 ets. Intricate genealogical tables of new 

 and fearful mien stared at us from black- 

 board, chart and printed page, and we 

 tried, with indifferent success, to look in- 

 telligent. 



Bateson, in his address as president of 

 the Britsh Association, capped the climax 

 when he added to the world-stupefying 

 clamor of the opening war with the follow- 

 ing verbal bomb: 



We must begin seriously to consider whether the 

 course of evolution can at all reasonably be rep- 

 resented as an unpacking of an original complex 



