Carus, Physiological Conditio7i of Consciousness. 137 



ZUCKERKANDL. Riechcentrum. Corpus striatum raotorisches ganglion. Man- 

 delkern hat nichts mil Riechcentrum zu tun. ^ 



In addition to the literature on the subject, Dr. Meyer in- 

 forms me that he had of late an interesting post mortem of an 

 old epileptic dement, with extensive destruction of the centrum 

 semi ovale and lenticular nucleus, the secondary degenerations 

 being exceedingly extensive, and, be it incidentally mentioned, 

 adding new information to our knowledge of the brain. 



Dr. Meyer does not agree with my theory of conscious- 

 ness ; nevertheless the facts which he kindly furnished me are, 

 to say the least, not unfavorable to my view. The diseases of 

 the various regions of the corpus striatum are attended with 

 vertigo, dementia, paranoia, torpidity of intellect, or melan- 

 cholia — all of which may be disturbances of the function of co- 

 ordinating and focusing the various elements of consciousness. 



As to the third point, I may not understand Prof Her- 

 rick's objection, but even in case there should be no organ of 

 co-ordination in the brain, there ought to be physiological 

 conditions on the presence of which the appearance of con- 

 sciousness depends ; and the problem of the nature of the con- 

 ditions is not "removed from the field of possible investiga- 

 tion." The ^^felt unity of feelings " which we call conscious- 

 ness, must have a definite relation to some physiological state, 

 and it must be possible to describe the mechanism of the phy- 

 siological operations required to bring about that attitude of an 

 organism, the psychical equivalent of which is consciousness. 

 Consciousness is undoubtedly the result of a co-operation of all 

 parts of the organism. If a man concentrates his attention 

 upon the sense of a sentence which he reads, the retina of his 

 eyes, the centre of vision in the occipital lobe, the centre of 

 language in the left hemisphere, the oculomotor nucleus in the 

 brain stem, the voluntary centres of the corpora striata which 



' Dr. A. Meyer should have included in this list his own investigations 

 " Ueber das Vorderhirn einiger Reptilien," Zeitschr. fur wiss. Zoologie, 1S92, 

 Leipzig, Engelmann ; and " Zur Homologie der Fornixcommissur und des 

 Septum lucidum bei den Reptilien und Saugern. Anat. Anz., X, 15. Fischer, 

 Jena. 



