721¢ 
“ The objection against the mind’s produ- 
cing the vital motions, drawn from their being 
involuntary, must appear extremely weak ; 
since there are a variety of motions equally 
independent upon our will, which yet are cer- 
tainly owing to the mind. Thus, as had been 
already observed, the contraction of the pupil 
from light, and the motions of the body from 
tickling, or the apprehension of it, undoubt- 
edly flow from the mind, notwithstanding their 
being involuntary. The shutting of the eye- 
lids, when a blow is aimed at the eye, is an- 
other instance of a motion performed by the 
mind in spite of the will; for, as the threat- 
ened blow does not, by any corporeal contact, 
affect the orbicular muscle of the palpebre, its - 
contraction must necessarily be deduced from 
the mind, moved to perform this action from 
the apprehension of something ready to hurt 
the eye: and if there are some who, by an 
effort of the will, can restrain this motion of 
their eyelids, yet this does not proceed so 
much from the mind’s making no attempt, in 
consequence of the apprehended danger, to 
close the palpebra, as from the superior eye- 
lid’s being kept up by a strong voluntary con- 
traction of its levator muscle. We cannot, by 
an effort of the will, either command or re- 
strain the erection of the penis; yet it is evi- 
dently owing to the mind: for sudden fear, or 
anything which fixes our attention strongly 
and all at once, makes this member quickly 
subside, though it were ever so fully erected. 
The titillation, therefore, of the vesicule semi- 
nales by the semen, lascivious thoughts, and 
other causes, only produce the erection of the 
penis, as they necessarily excite the mind to 
determine the blood in greater quantity into its 
cells.” 
Whytt’s view is best explained in the follow- 
ing passage of the same work :—‘* Upon the 
whole, there seems to be in man one sentient 
and intelligent pRrrnciPLEe, which is equally 
the source of life, sense, and motion, as of 
reason; and which, from the law of its union 
with the body, exerts more or less of its power 
and influence as the different circumstances of 
the several organs actuated by it may require. 
That this principle operates upon the body, by 
the intervention of something in the brain or 
nerves, is, I think, likewise probable; though, 
as to its particular nature, I presume not to 
allow myself in any uncertain conjectures ; 
but, perhaps, by means of this connecting me- 
dium, the various impressions, made on the 
several parts of the body, either by internal or 
external causes, are transmitted to and perceived 
by the mind ; in consequence of which it may 
determine the nervous influence variously into 
different organs, and so become the cause of 
all the vital and involuntary motions as well as 
of the animal and voluntary. It seems to act 
necessarily and as a sentient principle only, 
when its power is excited in causing the 
former; but in producing the latter it acts 
freely, and both as a sentient and rational 
agent.””* 
* Op. cit., 8vo ed., p. 290. 
PHYSIOLOGY OF THE NERVOUS SYSTEM. 
The third fasciculus of the Annotationes 
Academice of Geo. Prochaska was pub- 
lished in 1784. It contains the Essay on 
the Functions of the Nervous System. It is 
impossible to — too highly of this profound 
and accurate dissertation. Although short, it 
comprehends all the leading facts connected 
with the working of the nervous system, and 
affords abundant indications that its author had 
thought deeply on the subject. I know of no 
essay, of more modern date, which exhibits the 
same profound knowledge of nervous pheno- 
mena, and which is equally comprehensive. 
How it came to be so long neglected can only 
be explained by the too general incom 
of physiologists to appreciate his views. Yet 
his language is remarkably clear and precise, 
No one can have done more ample justice to 
his predecessors and contemporaries. His lite- 
rary research was extensive and accurate, and 
his historical summary is most interesting and 
instructive. The attentive perusal of this essay 
more frequently than once has impressed me . 
strongly with the conviction that Prochaska wasa 
man of the highest menta! oie rp and of great 
power of generalization, I shall rejoice to — 
see his work made easily accessible toall medical 
readers. a 
A brief summary of this important work will 
not be out of place here. Ley 
In the first chapter, the first seven sec= 
tions are occupied with an historical account 
of the views of preceding philosophers, begin- 
ning with Aristotle and Galen. {In the eighth i 
section, he remarks, “* At length we abandon 
the Cartesian method of philosophizing in this 
part of animal physics, he cntesetile v- 
tonian, being persuaded that the slow, nay, the 
most uncertain road to truth is that by hypo- 
thesis and conjecture, but that by far the more 
certain, more excellent, and the shorter 
that, que a posteriori ad causam ducit. Newta 
distinguished the inscrutable cause of the phy- 
sical attractions by the name ‘ force of attrac 
tion ;’ he observed its effects, arranged them, 
and detected the laws of motion, and thus 
blished a useful doctrine, honourable to huma 
genius. In this way we ought to proceed int 
study of the nervous system; the cause late 
in the nervous pulp, which produces 
effects, and which hitherto has not been det 
mined, we shall call vis nervosa ; its ¢ V 
effects, which are the functions of the ney 
system, we shall arrange, and ex : 
and in this manner we shall be able to cons 
a true and useful doctrine, que arti me 
novam lucem et faciem elegantiorem datun 
pro certo.” Haller, he admits, had pre 
used the term “ vis nervosa” to expr 
power by which nerves cause muscles to ¢ 
tract, but to Unzer he assigns the eredit 
having thrown the greatest light upon this 
ject, although he states that to not 
himself to the times in which he wrote and 
make himself more generally und d, 
still used the term “ animal spirits,” ; 
his doctrine was quite independent of such 
hypothesis. i 
o ae 
In the second chapter Prochaska gi 
. 
PIT. 
accomTE 
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