1890.] The Distribution of Plants. 821 
in some measure, the results of later investigations; but even his 
extraordinary genius, that seemed to compass the whole earth in 
its giant grasp, was forced at last, baffled and eluded, to yield the 
question and leave the field. 
Humboldt’s real service, then, was not so much in developing 
the laws of distribution as in boldly stating the problem and 
showing more clearly than it had ever been shown before how 
much there was to be accounted for. It needs but a slight ac- 
quaintance with his writings to feel convinced that the whole sub- 
ject of distribution had scarcely been worked beneath the surface ; 
the lines had been sighted and the stakes driven, but deeper ex- 
plorations were left for future workers. 
The well-known treatise of Alphonse De Candolle, “The 
Géographie Botanique Raisonnée,” * appeared just half a century 
. after the publication of Humboldt’s essay. Itis hardly too much 
to say that, compared with all that had preceded it, this great 
work showed such an increase of knowledge, with a breadth of 
view and capacity for generalization, as rendered it a permanent 
record of the sum total that had been accomplished up to the 
middle of the present century in this study. 
An examination of De Candolle’s treatise shows that there were, 
at that time, clear ideas regarding the relations of plants to physi- 
- cal conditions; that the shape of the area occupied by a species 
—approximately circular or elliptical—had been noticed; and 
disjoined species—those occupying widely separate areas—had 
received a certain amount of attention; that the greater part of 
existing species were then, as now, held to be of high geological 
antiquity, although it was also held that they originated by suc- 
cessive creations; and finally that the relations of species to 
genera, families, and higher groups were beginning to be studied 
in the light of facts of distribution. 
De Candolle had fairly done what, at this time, lay within the 
power of man to do. He had gathered an overwhelming array 
of facts, had marshalled them with orderly precision, had tried 
them— not wholly satisfactorily, it is true—with reference to their 
theoretical bearing, and had given them to the world ready to use. 
* Paris, 1855. 
