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out, it is necessary that these should be the only varia 
tions, if Natural Selection, in the strict sense of that term, 
is to come into action. Now, where transformation is at 
work, these individual variations will still occur, as the 
necessary accompaniments of sexual reproduction ; but in 
addition to these, changed conditions sometimes produce 
definite results on all the offspring ; and, as we have seen, 
these definite results sometimes appear in the individuals 
first subjected to changed conditions, and soon become 
fixed in the race. Wherever this process takes place, it is 
a transforming, not a selecting influence. Therefore, what 
ever cause produces definite results, tends to exclude the 
principle of Natural Selection. This, Mr. Darwin himself 
admits. 
“ It should not, however, be overlooked that certain rather strongly 
marked variations, which no one would rank as mere individual 
differences, frequently recur, owing to a similar organisation being 
similarly acted on—of which fact numerous instances could be given 
with our domestic productions. In such cases, if the varying indi 
vidual did not actually transmit to its offspring its new-acquired 
character, it would undoubtedly transmit to them, as long as the 
existing conditions remained the same, a still stronger tendency to 
vary in the same manner. There can be little doubt that the 
tendency to vary in the same manner has often been so strong that 
all the individuals of the same species have been similarly modified 
without the aid of any form of selection.”— {Origin of Species, p. y2.) 
“ The direct and definite action of changed conditions, in contra 
distinction to the accumulation of indefinite variations, seems to me 
so important that I will give a large additional body of miscellaneous 
facts.”—( The Variation, vol. ii., p. 2yy.) 
Thus, similar changes of outward conditions, acting on 
similar organisms, produce similar results on all the indi 
viduals subjected to their influence in such a way that 
there is no necessity to introduce the principle of Natural 
Selection. It is sometimes contended that in this trans 
mutation the nature of the organism is more important 
than the nature of the conditions.