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ATTENDING THE EXERCISE OF THE SENSES. 39 
in the mental act of Sensation; which term is now habitually used in Physiology, 
in exactly the same sense as Dr Rep understood it.* 
Accordingly, I think it may be confidently asserted,—although many physio- 
logists speak of reflex actions as not necessarily connected with sensation,—that 
the correct expression of these phenomena was truly given by Cuvier, in his Re- 
port to the Academy of Sciences on the Memoir of FLourens in 1822,—that an 
animal of which brain and cerebellum have been destroyed, and the medulla 
oblongata only remains in the cranium, is still capable of feeling Sensation, and 
of performing those acts which are immediately linked with sensation; and, in- 
deed, is dependent on sensations for the preservation of its life, which, in these cir- 
cumstances has been preserved for many months,—because it still breathes, and 
still swallows what is put into its mouth, &c.; but that, in these circumstances, it 
has no recollection of past sensations, shews none of its usual habits, cannot seek for 
food, or even avoid obstacles placed in its way; in short, is reduced to a state of 
stupor, more or less profound. In such an animal, of course, those judgments 
consequent on sensations, to which both Dr Rein and Dr Brown gave the name of 
Perceptions, and all more strictly Mental recollections and acts consequent on 
these, are manifestly suspended; and thus we acquire the certainty that the dis- 
tinction of Sensations and Perceptions, which we have seen to be of so much im- 
portance when considered metaphysically, is fully confirmed by physiological in- 
quiries, and, I may add, by researches in Comparative Anatomy; which have 
proved that the Cerebro-Spinal Axis is the part of the animal structure which fur- 
nishes the conditions, and supplies the instrument, of the ones et of mental phe- 
_ nomena; and the Brain and Cerebellum, superimposed on that structure within the 
skull, are those which minister in like manner to the other. This is, in fact, the 
only conclusion, as to the appropriation of these different parts of the larger masses 
of the nervous system to different acts or states of mind, which has ye theen satis- 
factorily established; and if we regard it, as I think we may, as an important 
guide to farther inquiries as to the use of the different portions of the physical 
instrument concerned in Thought, we ought also to regard it as an important 
indication of the value of the distinctions among the acts of thought, with which 
these different portions of the nervous system are connected. 
The other question is, as to the degree of modification which the exercise of the 
Senses, as well as other mental acts may undergo, in several anomalous conditions 
of the living body, especially in that to which the term Somnambulism, Extase, or 
Clairvoyance, has been applied. On this subject, which can only be elucidated by 
very carefully-conducted observations,—always likely to be impeded by peculiar 
* See Observations on the Physiological Principles of Sympathy, by the present Author, in 
Edinburgh Medico-Chirurgical Transactions, vol, ii. 

