26 
COMPARATIVE ZOOLOGY. 
rophyl is created, does real, constructive vegetation begin; 
then its mode of life is reversed—carbon is retained and 
oxygen set free. 
Most plants, and many animals, multiply by budding 
and division; on both we practise grafting; in both the 
cycle of life comes round again to the ovule or ovum. 
Do annuals flower but to die? Insects lay their eggs in 
their old age. 
Both animals and plants have sensibility. This is one 
of the fundamental physiological properties of proto¬ 
plasm. But in plants the protoplasm is scattered and 
buried in rigid structures: feeling is, therefore, dull. In 
animals, the protoplasm is concentrated into special or¬ 
gans, and so feeling, like electricity rammed into Leyden 
jars, goes off with a flash. 8 Plants never possess conscious¬ 
ness or volition, as the higher animals do. 
The self-motion of animals and the rooted state of plants 
is a very general distinction; but it fails where we need it 
most. It is a characteristic of living things to move. The 
protoplasm of all organisms is unceasingly active. 9 Be¬ 
sides this internal movement, myriads of plants, as well 
as animals, are locomotive. Rambling Diatoms, writhing 
Oscillaria, and the agile spores of Cryptogams crowd our 
waters, their instruments of motion (cilia) being of the 
very same character as in microscopic animals; while 
Sponges, Corals, Oysters, and Barnacles are stationary. 
A contractile vesicle is not exclusively an animal prop¬ 
erty, for the fresh-water Yolvox and Gonium have it. 
The act of muscular contraction in the highest animal is 
due to the same kind of change in the form of the cells of 
the ultimate fibrillae as that which produces the sensible 
motions of plants. The ciliary movements of animals 
and of microscopic plants are pronely similar, and in 
neither case indicate consciousne$flfubr self-determining 
power. 4 
