214 FUNCTIONS OF THE NERVOUS SYSTEM. 



last, being the result of experience. Thus, it has been well remarked by Dr. 

 Alison, that the changes which Emotions occasion in the countenance, ges- 

 tures, &c., of one individual, are instinctively interpreted by others ; for these 

 signs of mental affection are very early understood by young children, sooner 

 than any associations can be supposed to have been formed, by experience, 

 of their connection with particular modes of conduct ; and they affect us more 

 quickly and strongly, and with nicer varieties of feeling, than when it is 

 attempted to convey the same feelings in words, which are signs addressed to 

 the intellect. 



291. Many Physiologists and Metaphysicians are of opinion, that every 

 sensation actually experienced may become the subject of a perception at any 

 future time, though beyond the voluntary power of the memory to retrace ; 

 and the phenomena of dreams and delirium, in which these sensations often 

 recur with extraordinary vividness, afford much support to this doctrine. 

 Some of the instances upon record are remarkable, as proving that the sensa- 

 tions may be thus remembered, without any perceptions being attached to 

 them ; these sensations having been of such a nature, as not to excite any 

 notion or idea in the mind of the individual. A very extraordinary case of 

 this kind has been recorded, in which a woman, during the delirium of fever, 

 continually repeated sentences in a language unknown to those around her, 

 which proved to be Hebrew and Chaldaic ; of these she stated herself, on her 

 recovery, to be perfectly ignorant ; but on tracing her former history, it was 

 found that, in early life, she had lived as servant with a clergyman, who had 

 been accustomed to walk up and down the passage, repeating or reading 

 aloud sentences in these languages, which she must have retained in her 

 memory unconsciously to herself. Of the nature of the change, by which 

 sensations are thus registered, it is in vain to speculate ; and it does not seem 

 likely that we shall ever become acquainted with it. This is certain, how- 

 ever, that disease or injury of the brain will destroy this power, or will affect 

 it in various remarkable modes. We not unfrequently meet with cases, in 

 which the brain has been weakened by attacks of epilepsy or apoplexy, in 

 such a manner as to prevent the reception of any new impressions ; so that 

 the patient does not remember any thing that passes from day to day ; whilst 

 the impressions of events, which happened long before the commencement of 

 his malady, recur with greater vividness than ever. On the other hand, the 

 memory of the long-since-past is sometimes entirely destroyed ; whilst that of 

 events which have happened subsequently to the malady is but little weakened. 

 The memory of particular classes of ideas is frequently destroyed ; that of a 

 certain language, or some branch of science, for example. The loss of the 

 memory of words is another very curious form of this disorder, which is not 

 unfrequently to be met with : the patient understands perfectly well what is 

 said, but is not able to reply in any other terms than yes or no, not from any 

 paralysis of the muscles of articulation, but from the incapability of expressing 

 the ideas in language. Sometimes the memory of a particular class of words 

 only, such as nouns or verbs, is destroyed ; or it may be impaired merely, fco 

 that the patient mistakes the proper terms, and speaks a most curious jargon. 

 These cases have a peculiar interest, in reference to the final subject of our 

 inquiry. 



292. That the different portions of the Cerebrum have different functions 

 in the complex operations of thought, must be admitted to be by no means an 

 improbable speculation ; and it is well known that, under the name of Phre- 

 nology, or the Science of Mind, a systematic allocation has been made, of 

 what have been regarded as the several fundamental powers and faculties of 

 the mind, to certain parts of the Cerebral hemispheres. This was first 

 attempted by Gall, who stated that he was guided in his determinations, by 



