GENERAL SUMMARY. PATHOLOGICAL APPLICATIONS. 381 



occupy the mind, and its operations during the waking hours; so that in neither 

 state is there a remembrance of what passes in the other. There is usually 

 this difference, however; that the mental operations which take place in 

 Somnambulism are, like those o dreaming frequently suggested by what has 

 previously been occupying the mind; whilst these seem to leave no impression 

 to be retraced in the waking state, though all that passes in one fit of Som- 

 nambulism may be recollected in the next. This has been most remarkably 

 observed in the phenomena of that curious state, which is known under the 

 name of Double Consciousness ;* in this, the form of Somnambulism in which 

 there is a consciousness of external impressions, seems to alternate with the 

 condition of ordinary mental activity, and the individual leads (as it were) two 

 distinct'lives, recollecting in each condition what happened in previous states 

 of the same character, but knowing nothing of the occurrences of the other. 

 In regard to the curious forms of these affections, which are produced by 

 the so-called Mesmeric influence, the present views of the Author will be 

 stated in the Appendix. 



501. We have thus witnessed several varieties in the condition of the bo- 

 dily system, depending upon partial or complete suspension of the functional 

 activity of the Cerebrum, Cerebellum, and Sensory ganglia. There is no 

 normal condition of the Spinal system, which at all corresponds with these ; 

 since its operations are so closely connected with the maintenance of the Or- 

 ganic functions, that the suspension of them necessarily induces the cessation 

 of the latter. This is especially the case, however, in regard to the Respira- 

 tory ganglion; for the whole remainder of the Spinal Cord may be removed, 

 without the interruption of the movements which are dependent on that seg- 

 ment of it. Cases have occurred, however, in which the natural performance 

 even of these has been partially or entirely suspended ; and in which the 

 maintenance of life has for a time been effected, by a voluntary exertion of 

 the muscles of Respiration. The influence of the Will upon the general mo- 

 tor apparatus of Man, seems to predominate so greatly over the Reflex action 

 of the Spinal Cord, that few phenomena which are attributable to the latter 

 ordinarily present themselves ; these are manifested, however, when the in- 

 fluence of the Brain over any part is cut off, as is seen in certain cases of pa- 

 ralysis. These morbid conditions present us, also, with illustrations of other 

 effects of the interruption of the communication between the nervous centres 

 and particular sets of muscles. Thus, the influence of the Will may be cut 

 off, although that of the Instincts, Emotions, and Reflex Function may remain ; 

 or the respondence of the muscles to Emotion may be prevented, whilst they 

 are still capable of Voluntary control, or of Reflex action. Such cases seem 

 to point very clearly to three distinct primary centres of nervous agency ; 

 and to these, the Cerebrum Sensory Ganglia, and Spinal Cord (including the 

 Medulla Oblongata) have been here assigned as the instruments. We shall 

 next inquire into some other morbid conditions of the system, which seem 

 due to the irregular action of these; and in this we shall be chiefly guided by 

 the researches of Dr. M. Hall, which have been already slightly glanced at 

 ( 400,401). 



502. Of the Convulsive diseases, it appears that the greater part, if not the 

 whole, may be attributed to a morbid state of the Spinal System of nerves. 

 So completely does the power of producing convulsive movements appear 

 limited to that and to the Sensori-motor system, (no mechanical irritation of 

 the Cerebral substance being effectual in exciting such movements, 473,) 

 that, where convulsions present themselves during diseases which appear 



1 Much interesting information on this and other subjects, alluded to in this Section, may 

 be found in Dr. Abercrombie's Treatise on the Intellectual Functions. 



