CLIMATIC INFLUENCES 279 



other kind of animal. Man's migratory habits, both in- 

 herent and acquired, have fitted him for a life of vicissi- 

 tudes, and such a life inures him, as an individual, to all 

 extremes. On the other hand, the gorilla, as a genus, is 

 confined to a small habitat, which is uniform in climate, 

 products, and topography. Having been so restricted to 

 these conditions he is unfitted for any radical change, and 

 when such is forced upon him the result must always be 

 to his injury. 



In certain parts of the American tropics there is found 

 a rich gray moss growing in great profusion in these 

 localities and on certain kinds of trees. It is not confined 

 to any special level, but thrives best on low elevations. 

 Under favorable conditions it grows at altitudes far above 

 the surrounding swamps. Its character and quantity, 

 however, are measured by the altitude at which it grows. 

 It is an aerial plant, and it may be detached from the 

 boughs of one tree and transplanted upon those of an- 

 other. It may be taken with safety to a great distance, 

 so long as an atmosphere is supplied to it that is suited to 

 its nature, but when removed from its normal conditions 

 and placed in a purer air it begins to languish and soon 

 dies. If returned in time, however, to its former place or 

 one of like character, it will revive and continue to grow. 



What element this plant extracts from the impure air is 

 unknown. It cannot be carbonic acid gas, which is the 

 chief food of plants, nor can it be any form of nitrogen. 

 It is well known that the plant cannot long survive in a 

 pure atmosphere. Whatever the ingredient extracted may 

 be, it is certain that it is one that is deadly to human life 



