The Making of Species 
much as by their inherited tendencies. In this 
respect they differ very considerably from the 
higher animals. The peacock, for example, 
presents the same outward appearance! whether 
bred and reared in Asia or Europe, in a hot or 
cold, a damp or a dry climate, The same plant, 
on the other hand, differs greatly in outward 
appearance according as it is grown in a dry ora 
damp soil, a hot ora cold country. In his recent 
book The Heredity of Acquired Characters in 
Plants, the Rev. G. Henslow cites several 
examples of the celerity with which plants react to 
theirenvironment. On page 32 he writes: “ The 
following is an experiment I made with the 
common rest-harrow (Oxonzs spznosa, L.) growing 
wild in a very dry situation by a roadside. I 
collected some seeds, and also took cuttings. 
These I planted in a garden border, keeping this 
well moist with a hand-light over it, and a saucer 
of water, so that the air should be thoroughly 
moist as well. Its natural conditions were thus 
completely reversed. They all grew vigorously. 
The new branches of the first year’s growth bore 
spines, proving their hereditary character, but 
instead of their being long and stout, they were 
not an inch long, and like needles. This proved 
the spines to be a hereditary feature. In the second 
year there were none at all; moreover, the plants 
1 The white, pied, and “Japan” individuals are not more different 
from the type than some variations occurring in wild birds. 
22 
