522 THE CHANGING WORLD 



Inheritance 



New species are not formed by survival alone. They are only sorted 

 out in that way from variations that have appeared. 



After potentially better parents have been "selected" through the 

 processes of the survival of the fittest and the ehmination of the 

 unfit, then some effective way must be found for the transmission of 

 these life-winning qualities to the next generation, or there can be 

 no evolution of the race. Here enters again the old question of 

 whether the cumulative acquisitions of a lifetime are transmissible, 

 as Lamarck held, or whether there is some other possible way to get 

 from Ameba to man. 



Although no doubt Darwin sensed something of the uncertain 

 nature of acquired characteristics, he did not deny their adequacy 

 as a means of evolutionary advance, and in that regard Darwinism 

 offers no improvement over Lamarckianism. What he did do was 

 to emphasize the importance of inborn rather than environmental 

 characteristics, as of greater value in the selective process. It is not 

 so much what an animal becomes or accomplishes in its lifetime 

 that is of hereditary importance to the offspring, as what it has within 

 itself to accomplish. Among human kind, success in life may be more 

 of a family affair (heredity) than a matter of education (environment 

 and training). Inherent possibilities, whatever their origin, are 

 plainly transmissible, and furnish the needful material on which 

 selection may act for cumulative improvement. 



Darwin tried to imagine how acquired characters could become 

 inherent, and so transmissible along with other hereditary character- 

 istics. To this end he elaborated his supplementary pangenesis hy- 

 pothesis, which briefly is that specific determiners, or pangenes, are 

 formed by every part of the body. These pangenes, like instructed 

 delegates representing various constituencies, collect together to make 

 up the germ cells from which a new individual arises. When such 

 germ cells unfold their possibilities in development, every part of the 

 parental body, including acquired characters, is represented, and 

 consequently may reappear in the new individual. 



Pangenesis was a brilliant attempt to strengthen the weakest link 

 in the chain of explanation of how natural selection might give rise to 

 new species. There are too many ifs, however, to this delightfully 

 simple hypothesis. It must be remembered that it was suggested 

 before the astonishing story of the chromosomes was known, and 



