382 ENVIRONMENTAL CONDITIONS. 



not be too strongly impressed by the dicta of meteorological and 

 climatological science. They should be encouraged to leave the beaten 

 paths and to approach the climatological problems from new angles, 

 angles determined by the principles of physiology rather than merely 

 by past custom or by the principles of meteorology. It may readily 

 happen that some of the most satisfactory methods for ecological 

 climatology will be strenuously opposed by students of climatology 

 as this special science has been hitherto developed, but such students 

 may remember that the main reason why greater progress concerning 

 the relations of climate to organisms has not been made lies in the fact 

 that those interested in climate have seldom been seriously interested 

 in physiology, while most writers in physiology have had little active 

 interest in climate. What ecological climatology requires is funda- 

 mental study of the climatic conditions as these are effective to alter 

 physiological processes. Here there should be comparatively little 

 interest in the meteorological causes of climatic conditions; attention 

 is rather to be directed to the physiological effects of these conditions, 

 without confusing the main issue by considerations as to how the con- 

 ditions themselves have been brought into existence. 



The most general conclusion derived from our investigations is, 

 therefore, that very little real advance in this field is to be looked for 

 until many new methods have been devised and tested. This proposi- 

 tion may appear disappointing to some ecological students, and our 

 failure to place great reliance upon our own methods and results may 

 be regarded by some as a confession that the work itself has been 

 without valuable outcome. On the contrary, as has been repeatedly 

 stated and implied, we have been convinced, throughout this pro- 

 longed study, that the only present way to make progress in ecological 

 climatology is to utilize the available climatic records as far as possible 

 and to test every method for their interpretation that appears at all 

 plausible or promising. If some or all of the methods of integration, 

 etc., here employed shall finally prove to be without permanent value, 

 the present studies may have been useful in showing this to be true, and 

 they may stimulate subsequent workers to devise other and better 

 methods. Whether a method for handling climatic observations may 

 or may not be useful in the study of plant distribution can not be 

 known, of course, until it is subjected to rather thorough test. Our 

 climatic charts have been prepared to test, in this regard, some of the 

 most plausible methods that have been suggested. 



Turning to the results of the work itself, the following paragraphs 

 of the present section are to be read with the mental reservation that 

 the conclusions stated, as far as they are general, are but tentative; 

 they are known to be true only within the limits imposed by the 

 nature of the climatic data used and by the methods of interpretation 



