138 



VARIATION 



If a new race is produced by hybridization, then a new com- 

 bination of characters has been effected, and it is fair to assume 

 that the combination is richer in possibilities and possesses a 

 larger number of characters than did either parent. Mutation 

 teaches that new assortments of characters may take place, in 

 some cases at least, without hybridizing. 



If a racial character, as color or hairiness, is lost, we recognize 

 the new type and name it as a new creation. It may be more 

 valuable to us than its parent, but it must be recognized biolog- 

 ically as having lost something to which it was racially entitled. 



Again, if all normal characters acquire an unusual develop- 

 ment, relatively or absolutely, as in giants, or if their develop- 

 ment is abnormally arrested, as in dwarfs, we again recognize 

 the new departure, and it is a good mutation. 



Still again, if certain characters only undergo change in devel- 

 opment, while others remain normal, then relative values are 

 changed, the effect is altered, and we recognize a different type. 

 This, too, is a good mutation, provided the new relation persists. 

 All these changes can be worked with the normal characters 

 of the race, without the introduction of new characters or even 

 the supposititious aid of latent characters. Soberly considered, 

 these changes are none other than the student of biology would 

 expect, unless indeed racial characters are bound together much 

 more rigidly than present evidence would lead us to suspect. 



Summary. Not all variations are continuous and connected 

 with the type by insensible differences. Some deviations are dis- 

 continuous, with a tendency for future variations not reverting to 

 the main type but clustering about a new center of variability, thus 

 setting up a new type. Such a deviation is called a mutant, and 

 new strains may arise in this manner, as well as by the slower 

 Darwinian method of heterogeneous variation, out of which new 

 types are established by the slow process of selection. 



Both the experience of breeders especially with new varie- 

 ties in America and numerous instances of experimental evi- 

 dence show conclusively that new strains not only may, but in 

 actual practice do, originate in this manner, suddenly and com- 

 pletely, without any apparent preparation and with little tendency 

 to revert to the original or main type, which continues as before 



