132 



SCIENCE. 



[N. S. Vol. XIX. No. 473. 



mended is the difficulty of obtaining high- 

 grade material presented in an essentially- 

 geographical form. Inasmuch as this diffi- 

 culty arises from the relative inattention 

 to geography as a mature science, it is the 

 business of geographical societies to re- 

 move the difficulty. 



W. M. Davis. 

 Harvakd Ukiver.sity. 



( To he concluded. ) 



HOME UNSOLVED PROBLEMS OF ORGANIC 

 ADAPTATION. -'^ 



With the advent of the ' Origin of Spe- 

 cies ' became current the naturalistic inter- 

 pretation of organic nature, epitomized in 

 such phrases as 'natural selection,' 'sur- 

 vival of the fittest,' etc. So rapid and 

 general was the acceptance of this concep- 

 tion as a working hypothesis that in thirty 

 years, or within a single generation, Wal- 

 lace made bold to claim for it universal 

 recognition in the well known and oft- 

 quoted declaration, 'He (Darwin) did his 

 work so well that descent with modifica- 

 tion is now universally accepted as the 

 order of nature in the organic world.' 



As a general statement of the fact of 

 evolution, as the phrase may be literally 

 interpreted, it may, after fifteen additional 

 years of intense biological activity, be as 

 vigorously claimed and as readily con- 

 ceded. If, however, it be so interpreted 

 as to include the full content of Darwin- 

 ism and the all-sufficiency of natural se- 

 lection as the prime factor, with its details 

 of endless adaptations to environment, 

 whether physical or physiological, it need 

 hardly be said that consent would be far 

 less general or prompt. 



Moreover, with the highly metaphysical 

 and speculative deductions which, under 

 the caption of 'Neo-Darwinism, ' or, more 

 plainly, 'Weismannism,' which have 



* Address of tlie vice-president and chairman 

 of Section F, Zoology, St. Louis meeting, 1903. 



boldly assumed the omnipotence and all- 

 sufficiency of natural selection to account 

 for the least and last detail of organic dif- 

 ferentiation or constancy, widespread 

 doubt and open protest are too common to 

 elicit surprise or comment. 



It need hardly be pointed out at this 

 late day, though it is more or less persis- 

 tently ignored, that primitive Darwinism, 

 while essaying to explain the origin of 

 species, and emphasizing the importance 

 of natural selection as a means in the proc- 

 ess, did not in the least presume to account 

 for the origin of variation and adaptation, 

 which were recognized as fundamental and 

 prerequisite in affording conditions with- 

 out which natural selection must be hope- 

 lessly impotent. Nor, moreover, should it 

 be overlooked that while recognizing the 

 inseparable correlation of the factors just 

 mentioned and their essential utility either 

 to the individual or species in the majority 

 of cases, Darwin was free to concede and 

 frank in declaring the efficiency of many 

 other factors in the intricate and compli- 

 cated problems of organic evolution. 



The recent impulse which has come to 

 biologic progress by experimental methods, 

 and the remai'kable results which have 

 been attained thereby, may without exag- 

 geration be said to have raised anew many 

 an earlier doubt as well as brought to light 

 problems apparently beyond the scope of 

 the older explanations. It may not, there- 

 fore, be an extravagant assumption to an- 

 nounce the entire question of organic adap- 

 tations as open for reconsideration, in the 

 light of which no apology will be necessary 

 for directing attention to cei-tain phases 

 of the subject upon the present occasion. 



Among the many problems which recent 

 investigations and conclusions have 

 brought into better perspective as well as 

 sharper definition, and which might profit- 

 ably be discussed, the limits of a single 

 address preclude any very wide range of 



