NEW COMBINATIONS OF GENES 21 



of genes that tend to produce vigor and mental power. An- 

 other may carry another and different set of genes that produce 

 a degree of vigor and powder. When these two are mated, some 

 of the descendants receive both sets of genes that give vigor 

 and mental power; they show therefore a vigor and power 

 far beyond that of their parents. By successive matings of this 

 sort, any particular capability or quality may be carried far 

 beyond the degree in which it formerly existed. What may be 

 the limits of progressive evolution occurring in this way no 

 one can say. 



3. Third and perhaps still more important, as a result of 

 these recombinations of genes, characteristics may appear in 

 the descendants that have never occurred in their ancestors. 

 Examples of such results are abundant in animals and plants. 

 They are perhaps most obvious in relation to colors. To take 

 a well known example, we may begin with two races of 

 primroses, one red, the other white." Crossing the two, we 

 find in their descendants individuals having many other 

 colors: magenta, pink, many different shades of red, and 

 flowers with colors in blotches. In place of two colors we 

 have in the descendants a dozen or more different colors. 

 These are obviously due to the chemical interaction of the 

 materials derived from the genes of the two parent races. The 

 different descendants get different combinations of the genes 

 of the two parents. In development these genes give off 

 materials into the cytoplasm. There they interact, producing 

 many different results in different cases. There are known 

 great numbers of examples of the production of new colors, 

 and also of new forms, in this way. The same method of 

 action must apply to other characteristics that are less conspic- 

 uous and less readily defined; they must apply to vigor, 

 strength, special capabilities, and mental power. How far 



