cxl Journal of Comparative Neurology. 



The middle meningial artery is most liable to disease and its 

 superficial distribution is in this same area. 



Pachymeningitis hemorrhagica, then, is due, according to the 

 author, to passive engorgement of a compensatory nature, caused by 

 a process analogous to dry-cupping. This is brought about by a 

 shrinkage of the brain, which, owing to its suddenness, and to a de- 

 ficiency of cerebro-spinal fluid, has not been compensated for. 



The Knee Jerk.^ 



The knee-jerk is largely produced by reflex contractions of the 

 vastus internus and crureus muscles. The centre was located in the 

 4th and 5th lumbar segments of the cord in the Rhesus monkey (3d 

 and 4th of man). The efferent path is in the anterior roots of the 4th 

 and 5th lumbar nerves and was traced along the anterior crural nerve 

 to the muscles mentioned. The afferent path was found in the pos- 

 terior root of the 5th lumbar of Rhesus (4th of man, 6th of cat). 

 The afferent fibres arise within those muscles to which the efferent 

 fibres concerned with the "jerk" belong. 



It was found easy to abolish the conductivity of the afferent root 

 by cold, cocain, carbon dioxid, etc. for the "jerk" while reflex 

 stimuli from the skin were still transmitted. Perhaps the fibres for 

 the former are more delicate. 



The knee jerk is exaggerated by section of afferent branches be- 

 low those producing the jerk, which is explained as due, not simply to 

 the resulting relaxation of the muscles but to the interrupting of a 

 stream of afferent stimuli that passes from the ham-string muscles which 

 would exert an inhibitory influence. Excitation of the afferent fibres 

 coming from one set of antagonistic muscles induces reflex tonic con- 

 traction of the opposite set very readily. 



Some Sngrgestions Concerning Methods of Psychological Study. 



An interesting paper under the above caption appears in the 

 Transactions of the Wisconsin Academy IX, i, from the pen of Pro- 

 fessor J. J. Blaisdell. The suggestions are good and new, and 

 whether one shall say, as in another case, "what is good is not new, 

 and what is new is not good," or otherwise will depend very largely 

 upon one's prepossessions or prejudices or, as we say more euphemis- 

 tically, one's point of view. 



^Sherrington, C. S, Note on the Knee-jerk and the correlation of An. 

 tagonistic Muscles. Proceed. Roy. Soc. LIT. 32 a. 



