February 1, 1907] 



SCIENCE 



185 



cision thus gained and the natural character 

 of the classification proposed were pointed out. 

 A. W. Grabau, 

 Secretary of Section 



THE AMERICAN CHEMICAL SOCIETY. NEW YORK 

 SECTION 



The third regular meeting of the season of 

 1906-7 was held at the Chemists' Club, 108 

 W. 55th Street, on January 11. 



The Nichols medal, awarded annually for 

 the best paper read before the New York Sec- 

 tion, was presented to Howard B. Bishop for 

 his paper ' On the Estimation of Minute 

 Quantities of Arsenic' Favorable mention 

 was made of the paper of E. H. Miller and 

 J. F. Thompson on the ' Silver Platinum 

 Alloys ' and of the papers of F. B. Power and 

 Frank Tutin on the ' Chemical Examination 

 of ^thusa Cynapium ' and on the ' Chemical 

 and Physiological Examination of Ghailletia 

 Toxicaria.' 



The rest of the evening was devoted to a 

 symposium on the pure-food law by Messrs. 

 H. W. Wiley (address read by chairman), 

 Virgil Coblentz, E. Z. Doolittle and M. D. 

 Foster. Further discussion followed, in which 

 Messrs. Wm. J. Schieffelin, Albert Plaut, J. 

 B. F. Plerreshoii and L. L. Watters took part. 

 C. M. Joyce, 



Secretary 



DISCUSSION AND CORRESPONDENCE 



FACTS AND INTERPRETATIONS IN THE MUTATION 

 THEORY 



The foremost champion of de Vries's muta- 

 tion theory in this country undoubtedly is 

 Dr. D. T. MacDougal, and he has largely 

 contributed to the popularity of this theory. 

 In a recent article' he takes up certain objec- 

 tions made by various writers, and attempts 

 to show that they are without foundations or 

 opposed to the known facts. But the criti- 

 cism of the objections made by C. H. Merriam, 

 D. S. Jordan and the present writer fails to 

 convince, and only serves to demonstrate that 

 the vital points have been misunderstood. 



" ' Discontinuous Variation in Pedigree-Culture,' 

 Pop. Sci. Monthly, 69, Sept., 1906, pp. 207-225. 



Before I try again to give a review of my 

 objections to de Vries's theory, I shall prove 

 in detail that MacDougal's criticism of them, 

 as well as of those of Merriam and Jordan, is 

 unsatisfactory. It may appear as presumptu- 

 ous, when I take it upon me to talk in behalf 

 of the latter two gentlemen, who are well able 

 to take care of themselves,'' but I may be ex- 

 cused on the ground that I hold precisely the 

 same views, and am thus defending my own 

 opinions. 



I. MacDougal first takes up Merriam's con- 

 tention, that the study of geographical dis- 

 tribution of animals shows no evidence of 

 ' mutation ' (in the sense of saltation or dis- 

 continuous variation), since there are gradual 

 transitions, which point to a progressive de- 

 velopment of minute variations. This is not 

 admitted by MacDougal, because he maintains 

 (p. 209) that ' once a mutant has appeared, no 

 evidence of its distribution can be taken to 

 account conclusively for its origin.' Jordan 

 has answered this in the article just referred 

 to. But there is yet another aspect. Merriam 

 did not express any view as to the origin of 

 mutation (saltation) ; he only wanted to bring 

 out the fact that mutations, in the sense of 

 discontinuous variations, seem to be extremely 

 rare in nature, which is indicated by the fact 

 that, morphologically, varieties and even spe- 

 cies are often very close to each other, and 

 that, if there are cases where a discontinuity 

 is apparent, a closer investigation of the dis- 

 tribution, not only of the supposed mutant, as 

 MacDougal puts it, but of the mutant and its 

 allied forms, reveals the existence of inter- 

 mediate forms. 



With reference to this latter case, I should 

 like to make a few additional remarks. 

 Granted the existence of a connecting form 

 between two extremes, which appear to fulfill 

 the morphological requirements of mutation,' 



' See Jordan's rejoinder in Science, September 

 28, 1906, p. 399. 



' We always are to remember that, strictly 

 speaking, there is no morphological difference be- 

 tween iluetuating variation and mutation; the 

 latter can only be recognized by experiment, ac- 

 cording to de Vries, and also MacDougal. Thus 

 it is not correct to talk, as MacDougal does, of 



