222 THE DOCTRINE OF DESCENT. 
xX. 
The Geographical Distribution of Animals in the light of the Doctrine of 
Derivation, 
ALTHOUGH ever since the century of the great geo- 
graphical discoveries, material has been accumulating 
for a geography of plants and animals, the foundations 
of scientific botanical geography (apart from George 
Forster's observations) were first contained in Hum- 
boldt’s celebrated “Ideas on the Physiognomy of Plants” 
(Ideen zu einer Physiognomik der Gewichse). It is the 
first description of vegetal forms, comprising the entire 
area of the earth, and the manner in which, singly or 
combined, they lend a characteristic impress to the 
landscape of their region of distribution, and again on 
their side harmonize with the other factors of the scene. 
The celebrated founder of Climatology, who circled the 
terrestrial globe with lines of equal temperature, of 
equal inclination.and declination of the magnetic needle, 
and divided it into dry and rainy zones, knew better 
than any of his contemporaries that the animal and 
vegetal world depended on all these factors. Yet 
neither he nor his followers, before Darwin, rose higher 
than the description of Nature, which had already 
checked Buffon in his grand picture of Nature, ‘“ Les 
Epoques de la Nature.” 
A natural result of the extraordinary extension of 
