Introductory 19 
actually modifies its form and arranges its most 
essential organs; for these are its hours of expansion 
and of folding its petals fixed, and probably its 
season of appearance also. 
There is much greater similarity between animals 
and plants in their structure and their vital processes 
than the non-scientific public is disposed to recognise, 
widely though they may differ in the forms and 
action of their organs. The highest and the lowest 
plants, like the simplest and most complex of animals, 
are built up of minute cells, by whose subdivision 
growth proceeds. There is a circulation of vital 
fluids, an alimentary process by which the plant is 
fed, a breathing system by which the inhaled air is 
decomposed—one gas being retained, another given 
off, a reproductive process presenting close analogies 
with that of the animal kingdom, and the employ- 
ment of various “dodges” to effect certain ends that 
would do credit to animals with brain-power of a 
high order. 
So far from the sense of feeling being an attribute 
of animals alone, many plants are most irritable. 
Professor George Henslow, indeed, holds this irrit- 
ability chiefly responsible for the peculiar structure 
of the best known flowers, many of which are 
obviously modelled with a special view to the visits 
of certain insects. Then, again, the sensitiveness of 
the stems and tendrils of climbing plants is of a high 
order, and the plant’s response to the impression 
given by contact would certainly be regarded as 
evidence of intelligence if displayed by an animal. 
It is indeed essential that the reader of the following 
pages should at starting get rid of any preconceived 
