THE TEXTILE PLANTS 59 



who, while striving to improve his crop, must at 

 the same time take such crop as can be grown 

 year by year, without waiting for the best ulti- 

 mate product. 



Of course there are limits to the amount of x 

 development that is possible through such selec- 

 tive breeding. 



The plants operated with have certain heredi- 

 tary limitations, and these are pretty surely fixed 

 by long generations of inbreeding. When these 

 limits are attained by the practical plant devel- 

 oper, through the carrying out of such a system 

 of rotation as that just outlined for a good many 

 years, the best pure types of cotton represented 

 in the strains under investigation will have been 

 isolated, and the experimenter will find it diffi- 

 cult or impossible to make further improvement 

 by the mere process of selection. 



Then it will be necessary to introduce the 

 method of hybridizing, to give new vigor to the 

 plants and to produce new segregations and com- 

 binations of characters that will be equivalent to 

 the production of new varieties. And for this 

 purpose, as I have already suggested, the com- 

 bination of strains of the American cotton with 

 the Oriental ones, and also, doubtless, the utiliza- 

 tion of some hitherto neglected wild species may 

 be expected to prove of value. 



