The Inheritance of Acquired Characters 55 
to become diseased. The offspring sometimes showed defects 
in the corresponding organs. The authors suggest that some 
substance may be set free from the diseased organ which may 
be carried in the blood, and by diffusion get into the blood of 
the embryo, and directly affect the development of the corre- 
sponding organ. They attempted to test this hypothesis by in- 
jecting into the blood of a pregnant animal extracts from the 
diseased kidney of another animal, and while the authors do 
not appear so certain that similar effects are here also pro- 
duced in the organs of the embryo, yet this seemed to be 
the case. 
It will be observed that this transmission of an acquired 
character, if it really occurs, appears to be different from that 
of transmission through the egg, for it is the developing organ 
itself that is acted upon. 
These results may possibly have a bearing on Brown-Séquard’s 
work, since they seem to show that if an organ of an adult ani- 
mal (that is viviparous) is diseased, the same organ of the young 
may develop abnormally (or become diseased). Whether the 
two cases are really the same we do not know. In fact, it 
would be extremely hazardous to conclude even that they may 
be, until we know in what way epilepsy is caused — whether 
by a physical defect in the nervous system, or by bacteria, or 
by some other means. It should not be overlooked that the 
epilepsy was not present in the young when born, but developed 
later. There is urgent need that experiments of this sort be 
carried out on an extensive scale. 
Many other cases of mutilations have been cited to show 
that acquired characters are inherited. Defects in the parents 
are said sometimes to reappear in the young, and it is 
inferred that in some way the two things are connected. 
We are apt to overlook the fact that thousands of injuries are 
not inherited, and that a malformation appearing in the child in 
the same organ that had been injured in the mother or father 
may chance to occur at any time, and would be certain to arrest 
attention. We might err if we concluded in such cases that 
