4 BUTANICAL GAZETTE [JANUARY 
forest at the beginning of the dry season, and the burning sun 
having for some months heated through and dried the mass of 
felled trees, bushes, creepers, herbs, and the crowd of epiphytes 
that lived in the forest, he burns up everything, and in the 
ground now fertilized with the ashes and afterward cleared and 
leveled, he sows and plants. 
One can imagine the botanist’s joy. Those trees, at whose 
crowns and flowers he had gazed so often without being able to 
reach them, lie now, by such a “ Derrubada,” outstretched at his 
feet. In six different cases I have estimated the proportionate 
numbers of the species and individuals, and I have found that 
among 50-250 trees there were 27-91 species; that is, every spe- 
cies was represented on the average by two or three individuals. 
To us of the north, accustomed to the uniform forests of beeches, 
spruces, firs, etc., there is something most strange and overwhelm- 
ing in such a variety of forms. 
As in the trees, so in the other parts of the vegetation, the 
herbs and shrubs. The same thing is also true in the animal 
kingdom. Wallace says that more than 700 species of butter- 
flies live near Para, on the Amazon, while all Germany has but 
150, and England only 64 species. 
Now the question arises : What is the cause of this multitude 
of species in tropical nature? It seems obvious that these hun- 
dreds of trees, to speak only of them, living together in a forest 
of such small extent as this one near Lagoa Santa, must be simi- 
larly equipped in a physiological way, so that one species is not 
able to overcome and supplant another in the manner we know 
the beech, with us, is supplanting the oak. Every one of these 
tropical forest trees must shade as much, and at the same time 
be as well suited with the shade, as the others; that is, they are 
alike in fighting condition. In short, they must stand in quite 
the same relation to one another as the single individuals of the 
very same. Species; that is; just as the beech trees wre nba 
related, But how they have been able to reach this adaptation 
isa: Very difficult question, of which an explanation is at present 
an impossibility. Nevertheless, there is one condition that no 
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