286 THE AMERICAX XATURALIST. [Vol. XXXV I II. 



easily be overlooked, or they may be perceived only incompletely 

 and with difficulty, or they may be attributed to wrong causes. 

 It is also conceivable that certain influences produce effects not 

 because they are powerful, taking into account only short times 

 of operation, but because they are prolonged. 



This leads us to essay an analysis of 

 environment of an organism is all, everything, 

 the world and the universe outside of itself. One may say that 

 this definition is too comprehensive, that only immediate envi- 

 ronment is meant when the word environment is generally used. 

 Who can say that organisms and things are affected 'only by 

 their immediate environment } In fact we know that the contrary 

 is true in certain particulars. We know, for instance, that we 

 are daily affected by the sun — a remote body — quite as much 

 as by any part of our immediate environment. But we do not 

 know all the radiations and other influences from all the heav- 

 enly bodies in the universe, the effects of these upon our earth 

 as a planet, and what is upon it ; and yet these radiations still 

 unknown and unguessed, together with other unknown and 

 unguessed factors of environment, may operate as regularly and 

 as powerfully as any of the known and recognized factors. 



Among the recognized factors of the environment are some, 

 the effects of which are very imperfectly known, if they may be 

 said to be known at all. ' These will be seen in their relations to 

 other factors if an analysis, however imperfect, of the environ- 



; be giv 



all that consti- 



. The earth — rocks, waters, atmo- 

 sphere; the components, conditions, con- 

 tours, etc., of these. 



!. All other — whatever conditions 



prevail upon them ; their relative positions 

 to the earth and to each other. 



;. The forces emanating from and operating 

 upon these — heat, light, electricity, me- 

 chanical forces (gravity, wind, waves, ram, 



\. All living things — XV^vi parts, products, 

 and habits. 



. the list of factors suggested by this scheme. 



