3 i4 THE POPULAR SCIENCE MONTHLY 



another and even greater student of heredity, Gregor Mendel, was 

 doing the same thing in his experiments with garden peas, but inas- 

 much as Mendel's work remained practically unknown for many years, 

 Galton has been rightly recognized as the founder of the scientific 

 study of heredity. 



Of course, neither Galton nor any one else, who has followed his 

 method of dealing with the characters of organisms singly, ever sup- 

 posed that such characters could exist independently of other charac- 

 ters and apart from the entire organism. This is such a self-evident 

 fact that it may seem needless to mention it, and yet there have been 

 critics who have believed, or have assumed to believe that modern stu- 

 dents of heredity attempt to analyze organisms into independently 

 existing characters, whereas in most cases they have done only what the 

 anatomist does in treating separately the various organs of the body. 



Hereditary Kesemblances and Differences 



The various characters into which an organism may be analyzed 

 show a greater or smaller degree of resemblance to the corresponding 

 characters of its parents. Whenever the differential cause of a char- 

 acter is a germinal one, the character is, by definition, inherited; on 

 the other hand, whenever this differential cause is environmental the 

 character is not inherited. While it is true that inheritance is most 

 clearly recognized in those characters in which offspring resemble their 

 parents, even characters in which they differ from their parents may 

 be inherited, as is plainly seen when, in any character, a child re- 

 sembles a grandparent or a more distant ancestor more than either pa- 

 rent. Sometimes actually new characters arise in descendants which 

 were not present in ascendants, but which are thereafter inherited. Ac- 

 cordingly inherited characters may be classified as resemblances and 

 differences, though both are determined by germinal organization, or 

 heredity. There is, therefore, no fundamental difference between in- 

 herited similarities and dissimilarities. Heredity and variation are not 

 opposing nor contrasting tendencies which make offspring like their 

 parents in one case and unlike them in another; really inherited char- 

 acters may be like or unlike those of the parents. 



On the other hand, many resemblances and differences between pa- 

 rents and offspring are not due to heredity at all, but to environmental 

 conditions. By means of experiment it is possible to distinguish be- 

 tween hereditary and environmental resemblances and differences, but 

 among men where experiments are generally out of the question it is 

 often difficult or impossible to make this distinction. 



I. Hereditary Resemblances 



1. Racial Characters. — All peculiarities which are characteristic of 

 a race, species, genus, order, class and phylum are of course inherited, 



