1892.] The Difficulties in the Heredity Theory. 557 
Lamarckians suppose, by the inheritance of individual ten- 
dencies. But may not the favorable variations in the body be 
grouped to either outweigh or underweigh the unfavorable 
variations? This would be possible if combinations occurred, 
but we can readily see that combinations, such as we observe 
in the separate elements in the foot alone, completely neutral- 
ize each other so far as “survival ” is concerned; how the foot 
would neutralize the hand, or the foot and hand would neu- 
tralize the lumbar region.’ 
It is this consideration of single organs, the observation of 
their independent history, the rise of new compound organs, 
by steady growth from infinitesimal beginnings of their separ- 
ate elements, the combined testimony of anatomy and palæon- 
tology which force us to regard the theory of evolution by the 
natural selection of chance variations as wholly untenable. 
With the utmost desire to regard the discussion in as fair a 
spirit as possible, the explanations offered by the adherents of 
Weismann’s doctrine strike me as strained, evasive, and 
illogical.’ 
We can, however, by no means undervalue or dispense with 
natural selection, which must be in continuous operation upon 
every character of sufficient importance to weigh in the scale 
of survival. I need hardly remind you that this selecting 
principle was first discovered in 1813 by Dr. W. C. Wells, of 
Charleston, in connection with the immunity from certain 
tropical diseases enjoyed by negroes and mulattoes.’ 
The eliminating factor in selection is illustrated almost 
daily in cases of appendicitis. I regret I have not had time 
to ascertain whether or not this disease is considered due purely 
to accident or to congenital variation in the aperture of the 
appendix, which favors the admission of hard objects. If so, 
modern surgery is only benefiting the individual to the 
detriment of the race by its efficient preventive operations ; 
a have expanded this idea fully in recent papers upon the theory of evolution 
the horse. See “ Are Acquired Variations Inherited?” AMERICAN NATURALIST, 
February, 1891. 
See Weismann’s last essay, Retrogressive Development in Nature, Biol. Mem., 
trans., in press. 
3See Introduction of Darwin’s Origin of Species. 
