26 
COMPARATIVE ZOOLOGY. 
like an animal—a consumer, not a producer: not till the 
young shoot rises above the soil, and unfolds itself to the 
light of the sun, at the touch of whose mystic rays chloro- 
phyl is developed, does real, constructive vegetation be¬ 
gin ; 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 organs of motion (cilia) being of the very 
same character as in microscopic animals; while Sponges, 
Corals, Oysters, and Barnacles are stationary. A contrac¬ 
tile vesicle is not exclusively an animal property, for the 
fresh-water Volvox and Gonium have it. The muscular 
contractions of the highest animals and the sensible mo¬ 
tions of plants are both due to changes in the protoplasm 
in their cells. The ciliary movements of animals and of 
microscopic plants are precisely similar, and in neither 
case indicate consciousness or self-determining power. 
