idering other views which have been en- 
ertained respecting it. We shall now take a 
retrospective glance at the 
II. History or oprntons.—In the earlier 
ages of the world, before the true method of 
hilosophising on any subject was under- 
ood, it was considered as a sufficient ex- 
planation of any phenomenon to apply to it 
some abstract term, expressing a vague idea 
of a property inherent in the body which ex- 
hibited it, without attempting to ascertain the 
conditions of its operation.* Thus, all the 
‘phenomena of the movements of the heavenly 
‘bodies were attributed to the agency of a 
** principle of motion,” the laws of which were 
‘Searcely even sought for. In like manner, the 
simple optical fact—that, when the sun’s 
light passes through a hole, the bright image, 
if formed at a considerable distance from 
‘it, is always round, instead of imitating the 
figure of the aperture,—was attributed by 
Aristotle to the “ circular nature” of the sun’s 
light; whilst the mere consideration that the 
rays of light trave! in straight lines, would, if 
properly applied, have explained this pheno- 
menon, not only as regards the sun, but in the 
case of any other round Juminous body placed 
at a sufficient distance. It is not wonderful, 
then, that the still more intricate nature of the 
| phenomena exhibited by living beings, the 
obvious tendency of those presented by each 
" individual towards the same end, and the se- 
ductive simplicity of the hypothesis, should 
have induced the philosophers of that age to 
regard all vital actions as the immediate results 
| of one common cause; but that such a belief 
should have maintained its ground, with but 
| little alteration, to the present day, can only 
e regarded as a proof of the lamentable de- 
ficiency in truly philosophical views among the 
| cultivators of physiology. 
To the supposed cause of vital phenomena 
the term Life was applied by the older philo- 
_* This mode of philosophising has been very 
happily ridiculed by Fontenelle. ‘* Let us ima- 
gine,” he says, “all the sages collected at an 
( > age Pythagorases, Platos, Aristotles, and 
all those great names which now-a-days make such 
@ noise in our ears—let us suppose that they see 
the flight of Phaeton as he is represented carried 
ff by the Winds ; that they cannot perceive the 
rds to which he is attached, and that they are 
quite ignorant of everything behind the scenes. 
It is a secret virtue, says one of them, that carries 
off Phacton,—Phacton, says another, is composed 
certain numbers which cause him to ascend. 
A third says, Phaeton has a certain affection for 
‘the top of the stage; he does not feel at his ease 
when he is not there.—Phaeton, says a fourth, is 
not formed to fly ; but he likes better to fly than to 
leave the stage empty; and a hundred other ab- 
i 
Surdities of this kind, that would have ruined the 
reputation of antiquity, if the reputation of anti- 
At last 
me Descartes and some other moderns, who say, 
haeton ascends because he is drawn by cords, and 
because a weight more heavy than he is descending 
as acounterpoise. Thus to see nature as it really 
is, is to see the back of the stage at the opera.”— 
Quoted in Brown’s Lectures on Mental Philosophy, 
ct. Ve 
‘quity for wisdom could have been ruined. 
a 
LIFE. 
143 
sophers, who regarded it as a distinct entity or 
substance, material or immaterial, residing in 
certain forms of matter; and the cause, both 
of their organisation, and of the peculiar actions 
exhibited by them.* Every sect had its own 
notion of the origin and nature of this entity ; 
some regarding it as a kind of fire; others as a 
kind of air, ether, or spirit; and others, again, 
merely as a kind of water. The fable of Pro- 
metheus embodies this doctrine in a mytho- 
logical form, the artist being described as vivi- 
fying his clay statues by fire stolen from the 
chariot of the sun. Whatever was the idea 
entertained as’ to the character of this agent, 
all regarded it as universally pervading the 
world, and as actuating all its operations in 
the capacity of a life or soul; whilst a special 
division of it—a diyine particula aure—regu- 
lated the concerns of @ach individual organism. 
The opinions of Aristotle on this subject are 
very interesting, as presenting evidence of the 
tendency of his powerful mind to elevate itself 
above the level of his age, and as showing 
how completely even he was bound down by 
the prevalent tendency to hypothetical specu- 
lation, which seemed to offer so easy a solu- 
tion to all the mysteries of Nature. “ In con- 
sidering what holds the fabric of the universe 
together, and forms out of the discordant ele- 
ments a harmonious whole, he infers from 
analogy that it must be something similar in 
kind to that which forms and holds together 
an organised body, namely, a principle of life ; 
and that this principle, from the appearance 
of order and design displayed in the universe, 
must also have intelligence.” ‘ Besides this 
supreme animating principle (®ugts), the au- 
thor and preserver of all, there are many others 
which, by delegated powers, organise the bo- 
dies of animals and plants, so that all organised 
bodies whatever are to be considered as con- 
structed by and constructed for their animating 
principles, which, like the great animating 
principle, from being invisible to mortal eyes, 
indicate their existence, their energies, and 
their species, only through the medium of the 
structures which they form. Now, of these 
structures they are not only the efficient causes 
but, in his opinion, the formal and the final ; 
the causes of their motions, growth, and nu- 
trition ; the causes which give them a character 
and form; the causes on whose account they 
exist ; and even the causes of their being after- 
wards liable to corruption, as nothing is cor- 
rupted but what has been nourished, and has 
some time or other partaken of life. But, 
besides being causes of organised structures in 
these different senses, they are subordinate to a 
higher power, which prescribes their operations, 
not merely with reference to their separate and 
individual plans, but with a reference at the 
same time to that general and comprehensive 
* The term ¥vux" was applied by the Grecian 
philosophers to designate this animating prin- 
ciple, which included, with what is now known as 
the vital principle, the sensory and intellectual 
faculties. To the series of vital actions which, by 
many modern physiologists, is spoken of as Life, 
the term Zw» was given by the Greeks. 
