412 Goodale — Development of Botany Since 1818. 



interchange, even with Europe, has principally taken place 

 through Asia." 



This paper was communicated in 1859, on the eve of 

 the publication of Darwin's Origin of Species. At a later 

 date he applied the Darwinian theory to the possible solu- 

 tion of the problem, and came to the conclusion that the 

 two floras had a common origin in the Arctic zone, during 

 the Tertiary period, or the Cretaceous which preceded it, 

 and the descendants had made their way down different 

 lines towards the south, the species varying under differ- 

 ent climatic conditions, and thus exhibiting similarity but 

 not absolute identity of form. Before the American 

 Association for the Advancement of Science, in his Pres- 

 idential address, in 1872, he used the following language : 



"According to these views, as regards plants at least, the 

 adaptation to successive times and changed conditions has been 

 maintained, not by absolute renewals, but by gradual modifica- 

 tions. I, for one, cannot doubt that the present existing species 

 are the lineal successors of those that garnished the earth in the 

 old time before them, and that they were as well adapted to 

 their surroundings then, as those which flourish and bloom around 

 us are to their conditions now. Order and exquisite adaptation 

 did not wait for man's coming, nor were they ever stereotyped. 

 Organic Nature — by which I mean the system and totality of 

 living things, and their adaptation to each other and to the 

 world — with all its apparent and indeed real stability, should 

 be likened, not to the ocean, which varies only by tidal oscilla- 

 tions from a fixed level to which it is always returning, but 

 rather to a river, so vast that we can neither discern its shores 

 nor reach its sources, whose onward flow is not less actual 

 because too slow to be observed by the ephemerae which hover 

 over its surface, or are borne upon its bosom." 



Gray's active interest in the Journal continued until 

 the very end of his life. There were many critical 

 notices from his pen in 1887. His last contribution to its 

 pages was the botanical necrology, which appeared post- 

 humously in volume 35, of the third series (1888). His 

 connection with the Journal covered, therefore, a period 

 of more than a half a century of its life. 2 



The changes that were wrought in botany by the 

 application of Darwinism were far reaching. Attempts 

 were promptly made to reconstruct the system of botan- 

 ical classification on the basis of descent. The more suc- 



2 A notice of Gray's life and works is given by his life-long friend, J. D. 

 Dana, in the Journal in 1888 (35, 181-203). 



