264 COOK 



a much smaller crop the first year after its introduction, and 

 might have produced no seed at all if the tendency to abnormal 

 luxuriance of growth had not been checked by a long period of 

 dry weather. Other tropical varieties of cotton have consistently 

 refused to produce seed when introduced into Texas, even 

 though the same length of season would have been sufficient in 

 their home localities. 



With the superior conditions of growth supplied by our north- 

 ern summers most of the tropical varieties would be able, if 

 they utilized their opportunities properly, to develop even more 

 rapidly than they do in the tropics, and this result has been 

 reached with some of the Mexican varieties of corn. During 

 their first seasons in the United States they became greatly 

 overgrown and ripened scarcely any seed, but after a few years 

 they recovered their short-season qualities and became es- 

 pecially useful as extra-early varieties, like the " Mexican 

 June" corn. 



The conditions under which such experiments are usually 

 made are well calculated to intensify neotopism instead of hold- 

 ing it in check. It has been reasoned after the analogy of our 

 domestic varieties that fertile soil and thorough cultivation will 

 conduce to the early maturity so much desired. Moreover, it is 

 the regular practice to keep testing gardens and experimental 

 plots in the best of condition. The result is that the newly in- 

 troduced tropical variety is surfeited with the unwonted supply 

 of readily available food and moisture, which still further in- 

 creases the tendency to abnormal vegetative growth. 



Many such varieties have entirely failed of acclimatization 

 because they ripened no seed at all in the localities in which 

 the first experiment happened to have been made. Neverthe- 

 less, the inference is not warranted that such varieties cannot 

 be acclimatized in temperate regions. Experiments in the in- 

 troduction of new types of Upland cotton from Guatemala have 

 shown that the tendency to rank and sterile vegetative develop- 

 ment can be controlled by carrying the new stock far enough 

 to the north and placing it in comparatively sterile soil. In the 

 latitude of Washington the Guatemalan varieties of cotton 

 showed much more normal habits of growth, and made more 



