236 THE HISTORY OF CREATION. 
People who, by means of Banting’s system, at present so 
popular, wish to become thin eat only meat and eggs—no 
bread, no potatoes. The important variations that can be 
produced among cultivated plants, solely by changing the 
quantity and quality of nourishment, are well known. The 
same plant acquires an altogether different appearance, 
according as it is placed in a dry and warm place, exposed 
to the sunlight or placed in a cool damp spot in the shade. 
Many plants, if transferred to the sea shore, get in a short 
space of time thick, fleshy leaves, and the same plants 
placed in a particularly dry and hot locality get thin hairy 
leaves. All these variations arise directly from the cumu- 
lative influence of changed nutrition. 
But it is not only the quantity and quality of the articles 
of nutrition which affect and powerfully change and trans- 
form the organism, but it is affected also by all the other 
external conditions of existence, above all by its nearest 
organic surroundings, the society of friendly or hostile 
organisms. One and the same kind of tree develops itself 
quite differently in an open locality, where it is free on 
all sides, and in a forest where it must adapt itself to its 
surroundings, where it is pressed on all sides by its 
nearest neighbours, and is forced to shoot upwards. In 
the former case, the branches of the tree spread widely out ; 
in the latter, the trunk extends upwards, and the top of 
the tree remains small and contracted. How powerfully 
all these circumstances, and how powerfully the hostile or 
friendly influence of surrounding organisms, of parasites, 
etc., affect every animal and every plant, is so well known, 
that it appears superfluous to quote further examples. The 
change of form, or transformation which is thereby effected, 
