Mr. Home's Lecture, &c. 203 
who still continues to prosecute the subject ; and should the 
following observations contain any new materials, it is from 
that source that many of them are derived : for in my pecu- 
liar situation, I should little merit the honourable task assigned 
to me, were I not to avail myself of every advantage in my 
power, that could make the present lecture worthy the atten- 
tion of this learned audience. 
The principle of action in an animal, appears to be as exten- 
sive as life itself, and is almost the only criterion by which we, 
can distinguish living matter from dead. 
This action does not seem to depend so much upon struc- 
ture, as upon a property connected with life, which is equally 
extensive in its principle, and so far as we are yet acquainted, 
equally concealed from the researches of human sagacity. 
To acquire a sufficiently enlarged notion of this principle, 
we must not confine our inquiries to one set of animals, but 
must take into our view the whole chain of animated beings ; 
and from a review of the different circumstances in which it 
occurs, and the varied structure of parts upon which it is im- 
pressed, we shall have sufficient evidence that the fasciculated 
fibrous structure commonly met with is not necessary to its ex- 
istence, but only made use of for its support, and continuance. 
The structure which produces muscular action, varies so 
much in different animals, that we are at a loss to conceive 
how the effects should have the least similarity ; and it is in 
some cases, only from witnessing the actions that we can con- 
sider the parts as muscles ; since in nothing else do they bear 
a resemblance to the muscular structure in the more perfect 
animals with which we are best acquainted. 
We shall illustrate this observation by a description of the 
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