SPONTANEOUS MOVEMENTS IN PLANTS. 
369 
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 England 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 characters, 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 66 contractility ” common to all protoplasmic 
substance, and which are absolutely devoid of a nervous system ; 
and there are plants, unquestionable plants, which possess 
powers of spontaneous motion strictly comparable to those ex- 
hibited 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 appli- 
cation 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 in- 
stance 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- 
torise. 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,” (fig, 5), which are the results of the separation 
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 one extremity, 
with very fine cilia, varying from two to a large number. As 
soon as these minute bodies free themselves from the cell in 
which they are enclosed, the cilia begin to vibrate with great 
rapidity, the vibration being accompanied by a movement of 
rotation of the bodies themselves on their axis, occasioned 
apparently by rapid and spontaneous contractions ; the result 
VOL. XI. — NO. XLV. B B 
