832 
SPONTANEOUS MOVEMENTS IN PLANTS. 
universe not into three but into four kingdoms—animals, 
plants, protista, and minerals, the new kingdom of Protista 
including the most lowly organised forms of what are gene¬ 
rally considered animals and plants, from the Flagellate 
Infusoria to the Fungi, distinguished by the absence of 
sexes, and the mode of reproduction by gemmation or 
fission alone. The soundness of this new classification is not, 
however, admitted by the best remaining authorities in Eng¬ 
land or Germany. 
One of the most obvious distinctions between the animal 
and vegetable kingdoms consists in the possession by the 
former of a power of voluntary motion of either the whole or 
a part of the body, dependent on the presence of a distinct 
nervous system, which is absent in the latter; a distinction 
obvious enough when contrasting any of the higher forms of 
the two kingdoms, but which, like all other individual cha¬ 
racters, fails when pressed to too rigid a test. There are 
animals, so regarded by the best naturalists, and possessing 
other characters which compel us to refer them to this class, 
whose power of motion is confined to the i£ contractility” 
common to all protoplasmic substance, and which are abso¬ 
lutely devoid of a nervous system ; and there are plants, 
unquestionable plants, which possess powers of spontaneous 
motion strictly comparable to those exhibited by the lower 
animals. It may be interesting to collect together a few 
illustrations of this last-named fact, some of which appear to 
the writer scarcely explicable by the application of any of 
those laws which govern inert unorganised matter. 
The movements to which reference is here made belong in 
most cases to a part rather than to the whole of a plant; in 
some cases, however, we find the whole organism endowed 
with spontaneous motion of a very remarkable character. An 
instance of this occurs in the case of the regular undulating 
motion, exceedingly similar to that of some of the lower 
animals, characteristic of a class of Algae hence called Oscilla- 
toriae. The mode of reproduction of the Algae, the lowest 
class of the vegetable kingdom, to which the sea-weeds and 
the fresh-water confervae belong, is often obscure, and in some 
cases different distinct processes exist in the same species. 
In certain freshwater Algae, reproduction takes place by the 
formation of “ Zoospores,” which are the results of the sepa¬ 
ration and isolation of the protoplasmic contents of certain 
special cells. According to the observations of M. Thuret, 
who has paid great attention to this subject, these zoospores, 
which are of extreme minuteness, are ovoid in form, and are 
furnished, either over their whole circumference or towards 
