176 RAYMOND C. OSBURN Vol. XXII, No. 7 



The beneficial variations are of value to the organism in solving 

 its problem of existence and, very naturally, such variations 

 tend to insure that the organism shall live to maturity and 

 through its reproductive period. If a variation is inimical to 

 its possessor, then selection naturally eliminates the organism 

 that possesses such a variation and that is the end of that 

 variation, since, if its possessor does not live, the variation 

 cannot be perpetuated. 



Heredity is merely passing on to the next generation any 

 characters which may be a part of the germ plasm of the 

 organism. A species can find no way of continuing a variation 

 that is sufficiently harmful to cause the death of its possessor, or 

 even to pass on for very long a variation that is only mildly 

 disadvantageous. To indicate how important even a slight 

 advantage may be, allow me to quote from Prof. R. C. Punnett; 

 "If a population contains .001% of a new variety, and if that 

 variety has even a 5% selection advantage over the original 

 form, the latter will almost completely disappear in less than 

 a hundred generations." So, heredity becomes an important 

 factor for progress when coupled with variation and selection, 

 in that it gathers up the useful variations and concentrates 

 them in posterity. Or, as Prof. J. A. Thomson puts it, "The 

 true inwardness of heredity is a holding fast of that which is 

 good." 



A misconception of heredity lies in the notion that it can 

 accomplish anything more than merely to pass on to future 

 generations what has already become a part of the germ plasm. 

 Just as selection has no evolutionary importance aside from its 

 reaction on variations of different degrees of value in adapta- 

 tion, so heredity has no place in evolution except as it passes 

 along such characters as have been already selected out as of 

 importance in the life of the organism. Any new variation of 

 the germ plasm, of value, is in this sense selected and, by 

 heredity, becomes a part of the more advanced organism, while 

 any new detrimental variation is swamped by the struggle for 

 existence and is not permitted to be passed along by heredity, 

 because its possessor is eliminated as unfit to meet the condi- 

 tions of life. It is possible, of course, for a character to be 

 merely useless without being harmful, but such features of an 

 organism must play a very small part in evolution. 



