NATURE AND CAUSES OF ADAPTATIONS. (57 



The Kidney cotton, though commonly treated as a distinct species 

 under the name Gossypium peruvianum, agrees with the Sea Island 

 type in all its characters except the peculiar arrangement of the seeds. 

 If this should prove to be an adaptive feature the idea of specific 

 distinctness would have little left to support it. 



CULTURAL VALUE OF KIDNEY COTTON. 



The possession by the Kidney cotton of a definite weevil-resisting 

 adaptation would naturally raise a question regarding its cultural 

 value. It belongs to the Sea Island series, and has the long, fine fiber 

 and smooth seeds. The growing of the seeds together in masses would 

 still further facilitate picking and ginning operations. The bolls, too. 

 of this Guatemalan Kidney cotton, at least, are larger than those of 

 any of the Sea Island varieties. 



It is not likely, however, that any of the varieties of Kidney cotton 

 thus far known will be found of use in the United States, for all are 

 perennial " tree cottons." which have refused thus far to flower or 

 fruit in the period of growth allowed by the shorter summers of our 

 Temperate Zone. In tropical regions this objection would not hold, 

 and there appears to be no reason why the Kidney cottons should be 

 disregarded in the search for varieties suited to the various soils and 

 climates. The Trece Aguas Kidney cotton, for example, seems to 

 thrive well in a humid mountain climate considered by the natives to 

 be unfavorable for the annual Kekchi cotton, which is planted several 

 hundred feet lower down. 



THE NATURE AND CAUSES OF ADAPTATIONS. 



To explain how such characters as the weevil-resisting adaptations 

 arise involves an interpretation of general evolutionary questions upon 

 which the scientific world is still by no means agreed. Nevertheless, it 

 is evident that students of such subjects should conduct and describe 

 their investigations in accordance with some consistent plan or 

 policy, if their writings are to be understood or their facts intelligibly 

 recorded. Moreover, it would be scarcely reasonable to maintain that 

 such characters can be further increased by selective influence unless 

 it could be believed that they had been assisted in the past by the same 

 agency. 



It seems necessary to state that in the present report it is not 

 assumed that the weevil-resisting characters have arisen as direct pro- 

 tective responses to the injuries, or that they are the results merely of 

 stimulation or irritation caused by the weevils, as other writers on 

 evolutionary subjects might hold. Nor have they been thought of as 

 caused by selection in any strict sense of the word. Though consti- 

 tuting a most striking instance of the results of selective influence, it 



