238 Evolution and Adaptation 
izing the flower with pollen of another variety having pods 
of a different color. In these cases we do not know whether 
the color of the fruit is influenced directly by the foreign 
pollen, or whether the influence is through the embryo that 
develops from the egg-cell. The action may appear to be the 
same, however, in either case; but because it seems probable 
here that there is some sort of influence of one tissue on 
another, let us not too readily conclude that this is brought 
about through any such imaginary bodies as gemmules. It 
may be directly caused, for, instance, by some chemical sub- 
stance produced in the young hybrid plant. If this is the 
case, the result would not be different in kind from that of 
certain flowers whose color may be influenced by certain 
chemical substances in the soil. 
In the cases amongst animals, where the maternal tissues are 
believed to be influenced by a previous union with the male, as 
in the oft-cited case of Lord Morton's mare, a reéxamination of 
the evidence by Ewart has shown that the case is not demon- 
strated, and not even probable. Several years ago I tried to 
test this view in the case of mice. A white mouse was first 
bred to a dark male house-mouse, and the next time to a 
white mouse, but none of the offspring from the second union 
showed any trace of black. If the spermatozoa of the dark 
mouse are hypodermically injected into the body-cavity of the 
female, the subsequent young from a white male show no evi- 
dence that the male cells have had any influence on the ovary. 
The following facts, spoken of by Darwin himself, are 
not in favor of his hypothesis of pangenesis: “But it 
appears at first sight a fatal objection to our hypothesis 
that a part of an organ may be removed during several 
successive generations, and if the operation be not followed 
by disease, the lost part reappears in the offspring. Dogs 
and horses formerly had their tails docked during many gen- 
erations without any inherited effect; although, as we have 
seen, there is some reason to believe that the tailless condi- 
ee ae ay 
