ACQUIRED AND ABNORMAL CHARACTERS. 59 



this fact that they have not been transmitted. From 

 the cases presented in the following chapter, however, 

 it will readily be seen that the non-inheritance of a 

 character can only be determined by an exhaustive ex- 

 amination of the individuals in the collateral branches 

 of the family, as well as those in the direct line of de- 

 scent. If a character does not make its appearance in 

 a particular instance, it does not necessarily follow that 

 it has not been inherited, as it may be obscured or 

 made latent by the presence of some other character 

 that for the time is dominant in the organization. 



The heredity of acquired habits and abnormal pe- 

 culiarities should not be considered as exceptional, but 

 rather the result of some general law of the organiza- 

 tion that is constant in its action, and the supposed 

 cases of non-inheritance of a character will in all prob- 

 ability be found to be in accordance with it. 



It has been supposed that the transmission of func- 

 tional peculiarities of an organ involved the transmis- 

 sion of some corresponding structural change of the 

 organization, that gave rise to the abnormal modifica- 

 tion of its function. 



There are cases, however, in which a well-marked 

 functional derangement of certain organs, originally 

 produced by an injury to the nervous system, has be- 

 come hereditary, without the transmission of any ap- 

 parent malformation of the nerves themselves. Dr. 

 Eugene Dupuy has given some interesting illustrations 

 of this singular form of heredity, some of which he 

 observed as the assistant of Dr. Brown-Sequard, in his 

 experiments on Guinea-pigs, already noticed, while 

 others are the result of his own investigations. 



