34 IN THE GUIANA FOREST. 



With so few atmospheric changes it might be 

 supposed that the tropical forest would give rise to 

 little variation in animals and plants, yet, on the 

 contrary, it is here that nature runs riot as it were. 

 Physical environment has certainly some influence, 

 but we must look for the prime factor of differen- 

 tiation in the intense struggle for life. Man has 

 done little or nothing towards producing the 

 result, but everything is the outcome of energy 

 and selfishness. Nature has been lavish with her 

 gifts. Heat, light, and moisture are plenteously 

 bestowed, yet few trees can get room to 

 assimilate as much of the two latter as they need. 

 The forest is densely populated more so, in fact, 

 than any city ever was or could be. There is not 

 room for one in a thousand of the children born 

 therein, so that the fight for standing room is like 

 that of a crowd at a flte. It follows, therefore, 

 that every possible contrivance to gain a position 

 has been developed, and the result is almost per- 

 fection. The victory, however, has not been to the 

 few, but to the many. One species has progressed 

 on certain lines, but others have not been idle; 

 although the developments may be different in 

 each case the end is almost identical. 



The trees have succeeded in defending them- 

 selves against almost every animal. It is frue 



