instances which have been adduced, we have applied tests 
to show that the transmutation which takes place is by 
transforming influence, and not by Natural Selection. 
The effect of this argument can only be weakened in two 
ways, either by showing that changed conditions do not 
produce the effects attributed to them in the cases just 
cited ; or by a change of front, by understanding Natural 
Selection in some other sense than that which the strict 
definition of the theory indicates. 
We have already seen that the argument based upon 
the assumption that the modifications of “ the body ” can 
not be inherited is rendered invalid by the admission that 
the sexual elements may be modified, and that these 
modifications can be inherited. Sometimes the transform 
ing influences of changed conditions have been depreciated 
in order that the power of Natural Selection may be 
unduly appreciated. I am not aware that any writer has 
done this in a formal manner, and with full consciousness 
of what he was doing ; but by collating some passages 
from the works of Mr. Darwin, we shall be able to see 
how, no doubt unconsciously, this process of depreciating 
the transforming influence of changed conditions has taken 
place. Mr. Darwin asserts the efficacy of the principle as 
a law of nature, elsewhere he qualifies this statement ; 
then he appeals to our ignorance, or to the all-pervading 
mystery which is associated with the subject ; then he 
declares that it is not easy to discover how far a given 
effect is due to Natural Selection, and how far it is due to 
transforming influence ; then the efficacy of the principle 
of transforming influence is denied ; and finally, Natural 
Selection is substituted for the discarded principle of trans 
formation. We have now to consider what grounds there 
are for making these assertions, and how far the conclu 
sions arrived at can be justified.