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-Sequard'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 



