052 APPENDIX B. 



If this mode of reasoning is allowable, no fair comparison be- 

 tween diverse hypotlieses can be made. 



With these remarks on Professor Weismann's method at large, 

 let me now pass to the particular arguments he uses, taking them 

 seriatim. 



The first case he deals with is that of the progressive degra- 

 dation of the human little toe. This he considers a good test 

 case ; and he proceeds to discuss an assigned cause — the inherited 

 and accumulated etTects of boot-pressure. Without much diffi- 

 culty he shows that this interpretation is inadequate ; since 

 fusion of the phalanges, which constitutes in part the progressive 

 degradation, is found among peoples who go barefoot, and has 

 been found also in Egyptian mummies. Having thus disposed of 

 Mr. Buckman's interpretation, Professor Weismann forthwith 

 concludes that the ascription of this anatomical change to the 

 inheritance of acquired characters is disposed of, and assumes, as 

 the only other possible interpretation, a dwindling " through pan- 

 mixia " : " the hereditary degeneration of the little toe is thus 

 quite simply explained from my standpoint." 



It is surprising that Professor Weismann should not have seen 

 that there is an explanation against which his criticism does not 

 tell. If we go back to the genesis of the human type from some 

 lower type of primates, we see that while the little toe has ceased 

 to be of any use for climbing purposes, it has not come into any 

 considerable use for walking and running. A glance at the feet 

 of the sub-human primates in general, shows that the inner digits 

 are, as compared with those of men, quite small, have no such 

 relative length and massiveness as the human great toes. Leav- 

 ing out the question of cause, it is manifest that the great toes 

 have been immensely developed, since there took place the 

 change from arboreal habits to terrestrial habits. A study of the 

 mechanics of walking shows why this has happened. Stability 

 requires that the " line of direction " (the vertical line let fall 

 from the centre of gravity) shall fall within the base, and, in 

 walking, shall be brought at each step within the area of support, 

 or so near it that any tendency to fall may be checked at the 

 next step. A necessary result is that if, at each step, the chief 

 stress of support is thrown on the outer side of the foot, the body 

 must be swayed so that the " line of direction " may fall within 

 the outer side of the foot, or close to it ; and when the next step 

 is taken it must be similarly swayed in an opposite way, so that 

 the outer side of the other foot may bear the weight. That is to 

 say, the body must oscillate from side to side, or waddle. The 

 movements of a duck when walking or running show what hap- 

 pens when the points of support are wide apart. Clearly this 



