THE YOUNG SCIENTIST. 
127 
and taking a spiral twist as the creature 
moves about ; but in none can any mouth 
be discerned, and their antics, although 
energetic and comical, afford no certain 
a, motile 
oiuliiion of 
indications of either purpose or will. 
What are they ? animals or vegetables ? 
or something betwixt and between ? 
The first impression of any casual ob- 
server would be to declare in favor of 
their animality; but before this can be 
settled comes the question, what is an 
animal, and how does it differ from a 
vegetable ? and upon this the learned do 
by no means agree. One writer considers 
the presence of starch in any object a 
proof that it belongs to the dominions of 
Flora, while anotlier would decide the 
issue by ascertaining wiiether it evolves 
oxygen and absorbs carbon, as most 
plants do, or whether it evolves carbon 
and absorbs oxygen, as decided animals 
do. Dr. Carpenter asserts that the dis- 
tinction between Protophyta and Protozoa 
(first or simplest plants and animals), 
" lies in the nature of their food, and the 
method of its introduction, for whilst the 
Protopliyte obtains the materials of its nu- 
trition from the air and moisture that 
surround it, and possesses the power of 
detaching oxygen, hydrogen, carbon and 
nitrogen from their previous binary com- 
binations, and of uniting them into ter- 
nary and quaternary organic compounds 
(chlorophyll, starch, albumen, etc.), the 
simplest Protozoa, in common with the 
highest members of the animal kingdom, 
seems utterly destitute of any such power, 
makes, so to speak, a stomach for itself in 
the substance of its body, into which it 
injects the solid particles that constitute 
its food, and within which it subjects 
them to a regular process of digestion." 
Unfortunately it is very difficult to ap- 
ply this simple theoiT to the dubious ob- 
jects which lie on the borderland of the 
animal world, and no other theory that 
has been propounded appears to meet all 
cases. Some naturalists do not expect to 
find a broad line of demarkatioii between 
the two great divisions of living things, 
but others characterize such an idea as 
" unphilosophical," in spite of which, 
however, we incline towards it. 
Mr. Gosse, whose opinion is entitled to 
great respect, calls the Euglence " ani- 
mals " in his " Evenings with the Micro- 
scope," but from the aggregate of re- 
corded observations it seems that they 
evolve oxygen, are colored with the color- 
ing matter of plants, reproduce their 
species in a manner analogous to plants, 
and have in som_e cases been clearly 
traced to the vegetable world. It is, how- 
ever, possible that some Euglenw forms 
may bo animal, and others vegetable, and 
while their i)lace at nature's table is being 
decided, they must be content to be called 
Phytozoa, which, as we have before ex- 
plained, is merely Zoopliyte turned upside 
down. 
Some authorities have thought their 
animality proved by the high degree of 
contractility which their tissues evince. 
This, however, cannot go for much, as all 
physiologists admit contractility to be- 
long to the vegetable tissues of the sensi- 
tive plant, "Yenus' Fly-trap," etc., and 
a little more or less cannot mark the 
boundary between two orders of l)eing. 
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