346 PRESENT PROBLEMS IN EVOLUTION AND HEREDITY. 



presence of the fetus u})on female respiration {i. e., in the sternal re- 

 gion) and upon the pelvis. Xow, if it be true that the pelvis is larger 

 in the higher races than in the lower, I do not think that Dr. Lane can 

 sustain his point, because in the lo^yer races the fetus is carried for an 

 equally long period, during a much more active life, and in a more con- 

 tinuously erect position. Therefore, if these mechanical principles 

 were operating, the pelvis in the modern lower races should be larger 

 than in the higher. On the other hand, the form of the female i^elvis 

 in the higher races is one of the best established selecting or eliminat- 

 ing factors, a large pelvis favoring frequent births and the i)reserva- 

 tion of those family stirps in Avhicli it occurs. I mention this to show 

 how cautious we must be in jumping to conclusions as to kinetogenesis. 

 The transformism in all the external features of the skull, jaws, and 

 teeth may be attributed to inherited tendencies toward hypertro})h>- 

 or atrophy; but how about the convolutions of the turbinal bones or 

 the complex development of the semicircular canals and cochlea of 

 the internal ear and the many centers of evolution whi(di are beyond 

 the influences of use and disuse? These are examples of structures 

 wliich fortify Weismann's contention, for if complex organs of this 

 character can only be accounted for by natural selection, why consider 

 selection inadequate to account for all the changes in the body? 



])ifficulties in the natural-selection theory.—The answer, I think, is 

 readily given: We do not know whether use and disuse are oj^erating 

 upon the mechanical construction of the ear; we do know that the 

 organ can be rendered far more acute by exercise; but even if it were 

 true that habit can exert no formative influence, the ear is one of those 

 structures which since its first origin has been an important factor in 

 survival and may therefore have been evolved by natural selection. 

 Now, the very fact that selection may have to care for variations iu 

 such prime factors in survival as the ear, renders it the more difficult 

 to conceive that it also is nursing the minutia^ of variation in remote, 

 obscure, and uncorrelated organs. 



Even in the brief review of human evolution in the first lecture I 

 have pointed out eight indei)endent regions of evolution, upward of 

 twenty developing organs, upward of thirty degenerating organs. 

 A more exhaustive analysis would increase this list tenfold. Now, 

 where chance variation should ])roduce an increase in size in all the 

 developing organs, and a decrease iu size of all the degenerating 

 organs, and an average sizeiu all the static organs, we would have all 

 the conditions favoring survival. But the chances are infinity to one 

 against such a combination occurring unless the tendencies of variation 

 are regulated and determined, as Lamarckians suppose, by the in- 

 heritance of individual tendencies. But may not the favorable vari- 

 ations in the body be grouped to either out-weigh or under- weigh the 

 unfavorable variations? This would be jjossible if combinations oc- 

 curred; but we can readily see that combinations, such as we observe 



