Literary Notices. liii 



nerve cell, but during life inducing symptoms directly referable to the 

 central nervous system The tissue metabolism induced by the action 

 of these poisons upon the nerve cell we can only at present conjecture." 



c. J. H. 

 The Psychology of Sufficient Reason. ^ 



The problem of selective accomodation, according to the author, 

 is : How is it possible that from motor reactions, based entirely on 

 their utility to the organism, judgments of ' worth ' arise which are not 

 of the nature of reactions upon the environment but give rise to the 

 abstract concept ot truth ? 



The more developed the psychical organism the greater the degree 

 of selection manit'estei in the will acts. There is then a substitution 

 of imaginative processes for the external reaction and this imaginative 

 process is that which gives the sense of reality to our thinking. 



The sufficiency of the motive as well as that of the psychological 

 ground of a judgment lies in each case in the affective side of the im- 

 aginative complex. The paper is interesting as an attempt to trace 

 dynamic influence into a difficult sphere. c. l. h. 



Double Conduction in the Central Nervous System. 



Dr C S. Sherrington in the Proceedings of the Roy. Society 

 (Vol LXI, No. 373, 1897) publishes some very interesting experi- 

 ments which he interprets as showing that the fibers of the dorsal col- 

 umns of the spinal cord may conduct centrifugally, as well as centri- 

 petally. For example, movements of the hind limb and the perineum 

 were obtained by excitation of the funiculus gracilis after transection 

 of the medulla oblongata above the point of excitation, and these the 

 author interprets as due to the transmission of the stimulus down the 

 dorsal columns and through collaterals to motor nerve units. This of 

 course is directly opposed to the law of the " dynamic polarization of 

 neurons" of Cajal and van Gehuchten, which asserts that the neurite 

 is always cellifuEial, the dendrite cellipetal. The evidence does not, 

 however, >-eem perfectly clear that in Dr. Sherrington's cases it is the 

 same nerve fibers that perform the conduction in both directions- and 

 the whole subject, which is of great theoretical importance, offers an 

 inviting field for further study. c. j. h. 



* Urban. Princeton Contrib. to Psych. Vol. II, No. 2, Sept. 1897. 



' Compare also M. Allen .Starr in the Journal of Nervous and Mental Dis- 

 ease, Vol. XXIV, No. 8, p 452, who argues that all columns of the spinal cord 

 contain fibers passing in both directions. 



