THE 



POPULAR SCIENCE 



MONTHLY. 



OCTOBER, 1914 



PHENOMENA OF INHERITANCE 1 



By Pbofessob EDWIN G. CONKLIN 



PRINCETON UNIVERSITY 



A. OBSERVATIONS OF INHERITANCE 



THE observations of men in all ages have established the "fact that 

 in general "like produces like/' and that, in spite of many ex- 

 ceptions, children are in their main characteristics like their parents. 

 And yet offspring are never exactly like their parents, and this has led 

 to the saying that " like does not produce like but only somewhat like." 

 "What is meant is that there are general resemblances but particular dif- 

 ferences between parents and offspring. 



Individuals and Their Characters 



In considering organic individuals one may think of them as wholes 

 or as composed of parts, as indivisible unities or as constituent char- 

 acters; either aspect is a true one and yet neither is complete in itself. 

 Formerly in discussions on heredity the individual was regarded in its 

 entirety and when all hereditary resemblances and differences were 

 averaged it was said that one child resembled the father, another child 

 the mother. This method of lumping together and averaging resemb- 

 lances and differences led to endless confusion. In heredity, no less 

 than in anatomy, it is necessary to deal with the constituents of organ- 

 isms; in short, the organism must be analyzed and each part studied 

 by itself. Francis Gallon was one of the first to bring order out of 

 chaos by dealing with traits or characters singly instead of treating all 

 together. He made careful studies on the inheritance of weight and 

 size in the seeds of sweet peas, and on the inheritance of stature, eye- 

 color, intellectual capacity, artistic ability and certain diseases in man. 

 At the same time that Galton was thus laying the foundations for a 

 scientific study of heredity by dealing with characters separately, 



i Third of the Norman W. Harris Lectures for 1914 at Northwestern Uni- 

 versity on ' ' Heredity and Environment in the Development of Men, " to be pub- 

 lished by the Princeton University Press. 



VOL. LXXXIV. — 22. 



