July 20, 1906.] 



SCIENCE. 



83 



acter can be explained by the slow and gradual 

 accumulation of individual variations). The 

 whole book, ' Species and Varieties,' and the 

 two German volumes of ' Die Mutationsthe- 

 orie ' at once furnish, to one who understands 

 them aright, more than sufficient reason that 

 the old theory must, to say the least, stand 

 the test of the most rigid re-examination, and 

 the crucial test of verification by experiment. 



And what, pray, has ' the practically unani- 

 mous helief of zoologists and botanists the 

 world over ' to do with the merits of a new 

 theory? Did they not practically all, previous 

 to Lamarck, believe in special creation ? " The 

 old saying. Vox populi, vox Dei" wrote Dar- 

 win,^' " as every philosopher knows, can not be 

 trusted in science." 



In the same paragraph, this: ** * * a spe- 

 cies appears [sic'] to have arisen in a slightly 

 different way,' etc. (Of course it is an ele- 

 mentary species for which such a claim is 

 made.) Why question the veracity of the 

 author of the mutation theory by using the 

 word ' appears ' ? When, since the publica- 

 tion of Darwin's ' Origin,' has a scientific 

 fact been supported by a greater amount of 

 experimentation, more carefully and more 

 fully recorded, and not by one man only, but 

 by several workers? 



And if the critic asks, " How does it follow 

 that ' then in truth Darwinism can afford to 

 lose the individual variations as a basis ' ? " " 

 the answer is : because the bottom does not 

 fall out of the theory by such a loss. Other 

 material remains for natural selection to work 

 on. ' If it can be proved that a man eats beef- 

 steak for breakfast ' " it does not follow that, 

 * of course he could not have eaten bread.' 

 But, if it were demonstrated by reiterated ex- 

 periments that bread can do for a man all that 

 beefsteak does, then the man ' can afford ' to 

 do without the steak. Or, to make a more 

 relevant application, some men may breakfast 

 on steak, and others secure the same ends with 

 bread alone. 



Referring to his extended field studies of 



^= ' Origin,' 6th Am. ed., p. 143', 1883. 

 "Merriam, I. c, p. 243. 

 "Merriam, I. c, p. 243. 



plants, the critic says, " These studies have 

 convinced me that with plants, as with ani- 

 mals, the usual way in which new forms (sub- 

 species and species) are produced is by the 

 gradual progressive development of minute 

 variations." ^° Several pages of ' Species and 

 Varieties" are devoted to examples illustra- 

 ting that ' long-continued selection, alone, has 

 absolutely no appreciable effect ' in changing 

 the inner nature of a species or of a race, 

 whereas there is experimental evidence of an- 

 other factor by means of which such a change 

 is accomplished. The beauty of experiment 

 is that it convinces all, because given results 

 may be produced by all alike at will, and 

 * experiments are a repetition of things occur- 

 ring in nature.' " 



When one says he has 'passed in review 

 more than a thousand species,' we are con- 

 strained to ask, 'which, of at least three or 

 more commonly recognized kinds of species ? ' 

 Obviously, for example, the intergrading spe- 

 cies of a genus like Crataegus (hawthorn), 

 would prove nothing germane to the subject. 

 And if the best result of this laborious exam- 

 ination of species is, ' without finding a single 

 one which appears to have originated in this 

 way,' " one recalls the fascinating account in 

 ' Species and Varieties ' " of ' the first experi- 

 mental mutation of a normal into a peloric 

 race.' ^^ " The step from the ordinary toad- 

 flax to the peloric form is short, and it appears 

 [note the word] as if it might be produced by 

 slow conversion." ^° What a fine pseudo series 

 one might arrange with the normal Linaria 

 vulgaris and the L, vulgaris peloria at the 

 extremes, connected by the ordinary fluctua- 

 ting peloric variations ! ^^ The beauty of de 

 Vries's method is that it is possible ' to ar- 

 range things so as to be present when nature 

 produces * * * these rare changes.' ^^ In this 

 way it is known (not a matter of opinion) 



"Merriam, I. c, p. 243. 



'"P. 790 et seq. 



" ' Species and Varieties,' p. 430. 



'^P. 464. 



'^ ' Species and Varieties,' p. 473. 



^^ ' Species and Varieties,' p. 465. Italics mine. 



^ Of. also ' Species and Varieties,' p. 249. 



^ ' Species and Varieties,' p. 465. 



