142 
similar order, under a still more comprehen- 
Sive expression.* But it is not in every de- 
partment of science that the same facility in 
the attainment of general laws exists. Where 
the phenomena are of such a complex nature 
that the operation of the real cause is, as it 
were, masked by the influence of concurrent 
conditions, or where (as ofien happens in phy- 
Siology) the effects of the same apparent cause 
are totally different according to the instru- 
ments through which it operates, it is obvious 
that there will be great difficulty in the first 
stage of the inductive process—that of the clas- 
sification of phenomena,—so great, indeed, 
that it may be regarded as one of the principal 
obstacles to the advancement of those branches 
of science in which it presents itself. Of all 
the branches of physical science, that of me- 
teorology is the most obscure and apparently 
uncertain, and bears most resemblance to phy- 
siology. The changes which it concerns 
are daily and hourly occurring under our 
observation; and the general laws which 
govern them are tolerably well ascertained ; 
yet the mode in which their actions are com- 
bined is so peculiar, as hitherto to have baffled 
the most persevering and penetrating enquirers, 
in their attempts to explain or predict their 
operation. But no one thence feels justified 
in assuming the existence of any new or un- 
known cause, capable of controlling or sub- 
verting the influence of the rest; and sucha 
proceeding would not be justifiable, until all 
their possible modes of action have been ascer- 
tained: and put aside, leaving certain residual 
phenomena not otherwise to be accounted for. 
The peculiar difficulties which beset the in- 
vestigation of the laws of vital action have 
greatly retarded our acquaintance with them, 
and have even led to the belief that the induc- 
tive process is not applicable to them. These 
difficulties have arisen, in the first place, from 
the obstacles in the way of the collection of 
phenomena; secondly, from the peculiarly com- 
plex nature of these phenomena ; and, thirdly, 
from the vague hypotheses which have pre- 
vented them from being classed as simple facts 
on which generalisations are to be erected, or 
effects whose sources are to be ascertained, but 
which have clothed them in the delusive aspect 
of laws or causes. Until, therefore, the prin- 
ciples of philosophical induction are thoroughly 
understood, the peculiar combinations in which 
vital phenomena present themselves to our 
notice, their apparent dissimilarity from the 
changes which we witness in the world around, 
and their obvious adaptation to particular ends, 
might lead us astray into the labyrinth of un- 
profitable speculation with regard to the pre- 
siding agencies by which they are governed ; 
and the retrospective view which we shall pre- 
sently take will afford many examples of this 
error, even in recent times, and will in fact 
show that the legitimate objects of investiga- 
* Such would seem to be the tendency of certain 
recent speculations in regard to gravitation, mole- 
cular and electrical attraction, and chemical affinity. 
LIFE. 
tion, and the true mode of ing the 
are only now beginning to be understood. — 
When we observe the circumstances und 
which vital actions occur, we perceive that 
least two conditions are required for their p 
duction. The first is a structure in that pe 
liar state which is termed organised (see € 
GaNIsaTIon); the second is a stimulus 
some kind fitted to act upon it. Now thi 
no more than what we observe in the wo 
around, where every action involves two 
ditions of a corresponding character. W 
water is changed into steam, for example, i 
by the stimulus of heat. When a stone ff 
to the ground, it is by the attraction which 
mass of the earth exercises over its own. 7 
difference consists in the peculiarity of t 
actions exhibited by living beings, which a 
not identical with those elsewhere presented 
us, and which we cannot imitate by any p 
sical or chemical operations. Whilst 
chanical philosopher, then, refers to the p 
perty of gravitation as the cause of the effe 
just mentioned, the physiologist refers to 
capability of exhibiting vital actions, whi 
excited by certain stimuli, as the property 
the tissue which manifests them, us, wh 
he witnesses the contraction of a muscle, un 
the stimulus of innervation or of galvanis 
&c. he regards the effect as due to a propet 
of contractility inherent in the muscle, ¢ 
standing in precisely the same relation to 
organic structure, as gravity to matter in | 
neral. So far, however, the advance in our it 
quiry is more apparent than real; since it F 
fairly be said that, to speak of contractility 
the character of a body exhibiting contractior 
is merely a change in words without absolu 
gain. But, having done this, we are led 
inquire the conditions under which this cor 
tractility operates; and to analyse a number 
phenomena apparently dissimilar, so as to: 
tain the general law of its action. In this ma 
ner we proceed in regard to other classes of 
phenomena; and we shall thus acquire er 
our data are sufficiently precise and extensiy 
a knowledge of the properties of all the tiss 
or organised structures which compose t 
living body, and of the phenomena whi 
their single or combined operation will pi 
duce, under the influence of their respec! 
stimuli. re 
But the physiologist will not stop here. 
will seek to inquire to what these proper 
are due, which are so different from anyth 
exhibited by the same matter before it had 
come a part of the organised system. A 
if he consider the matter in all its be 
with a total dismissal of prejudice, he will 
unable, we think, to arrive at any other cone 
sion than that they are due to the act of orga 
sation, which, in combining the inorganie é 
ments into new compounds, and giv 
a peculiar structure, calls out or devel 
them properties which had previously exi 
in a dormant state, but required these ci 
stances for their manifestation. To this qu 
tion, however, we shall presently return, wh 
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