ANIMALS, PLANTS, AND MINERALS. 3 
Volvox as undoubtedly animal, other authors of equal repute 
acknowledge it as a plant. 
There are, indeed, even some naturalists who believe that 
there is no line of demarcation between plants and minerals, 
but that simple organisms can be, and are, formed out of in- 
organic matter; but, notwithstanding the ability and ingenuity 
with which these views have been supported, we hold such 
notions oe 08 purely speculative, and continue to maintain that 
the possesston of individual life and power of reproduction in 
the former, constitute at once, without further investigation, 
a broad and well-marked line of demarcation from the latter. 
Even when we compare plants with animals, so long as we 
confine our researches to the higher members of the two king- 
doms, the distinctions are evident enough; difficulties only 
occur when we look deeply into the subject and compare 
together those bodies which are placed lowest in the scale of 
creation, and stand as it were on the confines of the two 
kingdoms. It is then that we find the impossibility of laying 
down any certain characteristics by which all the members of 
the two kingdoms may be absolutely distinguished. We shall 
at present, therefore, confine our attention to those characters 
by which plants may as a general rule be distinguished from 
animals, but to which exceptions may be found when we com- 
pare particular individuals, leaving the more extended investi- 
gation of the subject to the future pages of this volume. 
In the first place, we find that plants hold an intermediate 
position between minerals and animals, and derive their nourish- 
ment from the earth and the air or water by which they are 
surrounded, and that they alone have the power of converting 
this inorganic or mineral matter into organic. Animals, on the 
contrary, live on organic matter, and reconvert it into inorganic. 
In other words, plants produce organic matter, and animals 
consume it. 
Secondly, plants are generally fixed to the soil, or to the 
substance upon which they grow, and derive their food immedi- 
ately by absorption through their external surface; while animals, 
being possessed of sensation and power of voluntary motion, 
can wander about in search of the food that has been prepared 
for them by plants and by other animals, and which they receive 
into an internal cavity or stomach. Plants are, therefore, to 
be regarded as destitute of sensation and power of voluntary 
motion, and as being nourished from without ; while animals 
are possessed of such attributes, and are nourished from within. 
Thirdly, the action of plants and animals on the atmosphere 
is different. Thus, during the process of what has been called 
assimilation, plants decompose the carbon-dioxide of the air 
or water in which they are growing, and, uniting the carbon, 
which is obtained from this decomposition, with the elements 
of water, to form starch or some other carbohydrate, restore 
B2 
