Io8 MAN, — THE ANIMAL 



in mind that the theoretical aspects of heredity 

 are still in obscurity. It is an easy task to de- 

 scribe cells, to explain the nature and purpose of 

 food or to designate the cause of the biological 

 diseases, although much remains to be learned 

 about these subjects, in comparison with a descrip- 

 tion of the problem of heredity. The uninformed 

 write and speak freely concerning this illusive 

 theme. The reader is asked to note carefully the 

 places where the description of proved facts ceases 

 and the discussion of theories about heredity 

 begins. 



Heredity Is the name for one aspect of proto- 

 plasmic activity in the study of which we attempt 

 to learn something of the history or inheritance 

 of protoplasm. In this brief study we shall come 

 to realize, the writer believes, that protoplasm 

 Is more than so many chemical elements having a 

 certain pattern and physical appearance. It Is a 

 part of the past Influencing the activities of the 

 present. 



Heredity must be thought of as a general term 

 which Is used to describe the repetition of parental 

 characters in offspring, and so It Is customary to 

 say that the child Inherits from Its parents or that 

 It has such and such a parental inheritance. The 

 same terms are used In the transmission of prop- 

 erty from parent to child, but there is this dis- 

 tinction, that the property Is a material substance 



