TRANSACTIONS OF THE SECTIONS. 93 
medium of the muscular sense, as the images reflected, or refracted in telescopes are 
the signs of external objects to the eye. Animals have adjustments ready-made : 
man has to learn his. To see and to touch, as an artist, or even in the common 
usages of life, a man just couched is as an infant; till he can adjust he sees, as we 
do with an unadjusted telescope, merely a vague light. This gives rise to search. 
To see with intelligence, we must look, that is, evert the combined adjustments : this 
constitutes an appreciable distinction between sensation and perception. The unad- 
justed impressions pass the mind as vague trains of thought, linked and associated 
sequences, the machinery of reveries and dreams. That searching to obtain well- 
defined perceptions is effected by adjustments, attention to our own working observa- 
tion will afford abundant proof; but a more protracted attention is necessary to 
prove, and to convince a man, that his memory and powers of conception equally 
depend on the mind’s perception of a reiteration of the adjustments of sensation. But 
that this is so we have proof, in the corporeal actions induced by conception being 
like those produced by sensation in the presence of the objects. Thus conception of 
savoury food excites secretion in the salivary glands—the conception of an insult 
excites the feelings and gestures of anger, &c. In the power of forming and giving 
fixity of tenure to conceptions men differ widely. It is to this power Dr. Johnson 
alludes, when, in his Tour to the Hebrides, he says, that whatever can make the past, 
the distant and the future prevail over the present, raises us in the scale of thinking 
beings. Now Dr. Darwin and Sir David Brewster have shown that these concep- 
tions are effected by adjustments of the body; in other words, that the “‘mind’s eye”’ 
is, in fact, the body’s eye. To have vivid conceptions disposable by our volition, 
forms the orator, the poet, the sculptor and the painter. After numerous illustra- 
tions of this faculty and allusions to it by the poets, the author stated that these 
sensations, perceptions and conceptions do not exist in an insulated state; the ad- 
justments by which they are affected are so linked and associated by retransmissions 
through the brain to the other organs of sense, that they reciprocally call up each 
other. This linked association of adjustments he took to be the machinery by which 
the association of our ideas is effected, and that the propensity of our structure to these 
functional adjustments constituted all we had of ideas which had been denominated 
innate; and he considered that this reciprocating perception from different sources 
of sensation (as the eye and ear) gave birth to the ideal theory of ‘ species, images 
of forms and colour of things without their matter,” of the old metaphysicians. In 
conclusion, the author contended that Mr. Hume’s opinion on the non-existence of 
the idea of power, and of cause and effect (except as antecedent and consequent), 
and the arguments and facts adduced against that opinion, receive an elucidation 
from the consideration of the modes of action of the muscular sense, but of which 
neither Mr. Hume nor his critics could at that time have been apprised, as the dis- 
covery had not been completed. 
Yet these impressions (our guides in all corporeal exertions) belong alike to men 
and all inferior animals, and must have been at all times, and in all places where 
muscular exertions have occurred. Yet such is the law of sensation, that the mind 
passes this muscular feeling unnoticed, and attends solely to his perception of the 
object by which the sensation was excited. Thus the attention of the seaman who 
heaves the lead is directed only to the contact of the lead when it touches the bot- 
tom. Every boy who throws a stone, every horse on its approach to a leap, estimates 
its power by these feelings, although thinking at the time only of the distant object 
of its aim. I think any man capable of making his sensations the subjects of his 
thoughts, may satisfy himself that our ideas of cause and power have their source 
in these and like evanescent muscular feelings or impressions. 
Is it not, too, from similar feelings of muscular power, recognised from day to day 
to be the same which we have felt from our earlier years, that we are assured of the 
continuance of our personal identity? 
On the Cause of the Blood’s Circulation through the Liver. 
By Cuarwtes SEARLE, M.D. 
After alluding to the powers which circulate the blood in the system generally, the 
author declared it to be still a problem by what combined forces the portal circula- 
