( 25 ) 



liciiiispliere. Here, if ;iiiv\vIicm-c, tVoni a pliysiolog'it'al point, of \ic\v, 

 is it clear that the endings of tlie e. callosum arc to be found in 

 tliose cortical layers in whicli the preinnervatory action especially 

 takes place. 



Without doubt, in the higher mammals also, where the c. callosum 

 has been cut, symptoms of lesion must be present, temporary perhaps, 

 but nevertheless constant. They have, however, not been discovered 

 as yet in clinical investigation. The asymmetrical function of the 

 cerebrum of man, added to the possibility of applying more delicate 

 methods of investigation, bring, in the case of disturbed co-ordi- 

 nation of the hemispheres, irregularities to light as described by 

 LiEPMANN, Heilbronner and others. That anatomy too, assists lis to 

 understand the manner of the termination of the c. callosnm and 

 especially the nature of the symptoms observed, can be assumed from 

 what has been found in the cat. It is by no means impossible that 

 still more complicated connections are present in man. A careful 

 cytoarchitectonic study of the cortex cerebri, in cases where the callosal 

 comiections have been severed before death, will throw light upon 

 this point. 



Anatomy. — ''On the inc'scjicep/Kilic nucleas and root of the 

 N. Tri(/enuims. By Dr. C T. van Valkeni3URO. (Communicated 

 by Prof. L. Bolk). 



(Communicated in tlic meeling of March 25, 1911). 



Among the brain nerve nuclei in man already known to us, the oidy 

 one about the functions of whicli we do not know anything with 

 certainty is the mesencephalic cell-group from which a portion of 

 the trigeminus fibres originate. Histology, anatomy, embryology, 

 experiments and clinical observations with pathalogical-anatomical 

 researches, none of these have succeeded in solving the riddle of 

 the function of this nucleus. 



After a |)eriod when sensoi-y functions were atti-ibuted to the 

 above nucleus and i-oot (Merkel, Wernicke, Meynkrt), there came a 

 time when its motor character was universally accej)ted, chiefly on 

 the base of experiments in degeneration (Forel, Breoman, II. v. 

 GuDDEN, S{ inzo-KuRE), l)ut partly also owing to histological 

 research (K()LL1ker, Cajal etc.), while of late the sensoi'y nature of 

 these cells and the afferent character of their neui'ones has again 

 found considerable snpport (Jounston, v. Londkn). 



This being the case, it may be exj)ected o priori that (he oi»inioiis 



