The Inheritance of Acquired Characters 63 
They are collected from all parts of the system to constitute 
the sexual elements, and their development in the next genera- 
tion forms a new being. . . .” 
A few experiments have been made to test this view. Galton? 
transfused the blood of one variety of rabbit into the veins of 
both sexes of another species, and then bred together the latter. 
If there are gemmules in the blood, the germ-cells of the rabbits 
containing the transfused blood might possibly show the influ- 
ence of the other variety. No evidence of such an influence 
was found. 
Darwin did not admit that this experiment was decisive, and 
Galton himself admitted that the results are not convincing. 
Darwin thought that the few gemmules present in the blood 
at any one time might not succeed in supplanting the similar 
kinds of gemmules supposed to be already present in the germ- 
cells. 
Another experiment was carried out by Romanes. Wild 
rabbits supplied the blood, and Himalayan rabbits received it. 
Several transfusions were made. In one case the blood of 
three wild rabbits passed through the veins of the domesticated 
individual. No evidence of any “foreign” influence was found 
in the offspring. Romanes said later that he had discovered 
that this experiment could not have been expected to give any 
positive results, because rabbits when crossed do not produce 
young having intermediate character. The force of the admis- 
sion is not very convincing, however, for the offspring might 
still have been expected to show the effects — if such influences 
are transmitted in this way — of the dominant breed, if this had 
been used to supply the transfused blood. Moreover, Castle 
has shown that in some breeds of rabbits certain characters at 
least are intermediate in the hybrid — the length of the ears, for 
example. 
Other zoélogists who have refused to accept the doctrine of 
the inheritance of acquired characters — Weismann, for instance 
— have nevertheless used another idea contained in Darwin’s 
1 Proc. Roy. Soc., 1871. 
a 
