178 ECOLOGY 



insight which connect mere description of the living form with the 

 vital phenomena of the animate world. 



Individuality and independence, however, had first to be woven 

 from the weakest as well as the strongest threads which unite the 

 " sciences of the earth," essentially geographical in substance, with 

 the vital phenomena of the plant and animal kingdoms. 



Physiology had taught how, with the aid of physics and chem- 

 istry, experiments could be made in the laboratory; it was obvious 

 that these experiments could be repeated out of doors, where the 

 changing play of nature's forces could be observed and fresh data 

 obtained, which later could serve as a basis for further experiments 

 in the laboratory. 



At the same time this new tendency took strict account of the 

 morphological development of those organs which, independently, 

 according to their adaptation to the environment, determine to what 

 biological form a plant or animal belongs. The ability of a plant 

 to perpetuate its existence as a tree with deciduous or evergreen 

 leaves, as a perennial whose powers of rejuvenation have endured 

 for centuries, as a weed dying after the quick ripening of its seed, 

 or else as a freely swimming or submerged w r ater-plant, or a plant 

 exposed to the stress of storms and winds, is just as important 

 from the ecological standpoint as are the various means of loco- 

 motion developed by animals for the purpose of securing nourish- 

 ment, such as springing, running, creeping, fluttering, and flying 

 through the air, or wriggling through the dark earth, swimming 

 freely on the surface of the water, diving in its shallows, or else 

 banished for life to the depths of the ocean. 



We find the greatest variation in vital conditions in passing from 

 pole to pole, from the ocean to the ice and snow of the mountain 

 peaks, from the sun-scorched desert to woody and shady valleys, 

 or to the cool caves hidden in the cliffs where is seen the greenish 

 glimmer of the Schistostega. For each change in the vital condi- 

 tions we find specially adapted forms of animal and plant life, and 

 in the fundamental principles of animal and plant geography we 

 find the earnest endeavor to contrast the more physiographical 

 details of distribution with the dependence of the adapted form 

 upon the environment; this latter, with its great biological im- 

 portance, being more especially the province of the zoologist and 

 botanist. 



In this manner has the study of ecology come into being, and, 

 since it has been most clearly and easily followed in botany, the 

 word in its modern meaning has come to denote more especially 

 the ecology of plants. Therefore the honor to address this Congress 

 upon the subject of ecology has been given to a botanist, who is 

 a plant geographer as well. 



