( 346 ) 



Physiology. — "()// Ihc fad a/' sciisihil' sL-'in-iirciis 'hjiiKj mean 

 in II i-i'nlrijh'hil ilirciiioii.^^ Bv Dr. (i. van lvi.)M?KRK. (Coin- 

 iimiiiL-;iU'(l l)v Pmf. V. Winki,kr). 



(Cuminunicatccl in the inccliiiy of Ucluber 31, i'JUo.) 



Tlir uiaiiiKM- ill which, in our (v\i>ci-iiiiciils on (h),us, ') ihc isoljiled 

 root-area of th(^ skin (derniatoina), dies awav, if the rool lo whirl» 

 it corresponds, is killed In coniin-cssion, ,iii\('s rise lo the supposition 

 that this peculiar series of uraduallv uan-owiuu and shiMukinii- aivas, 

 pi-oceeilinu' from ventral to dorsal part. IVcnn the lateral |tarts tow anls 

 the centrum, uia\ he caused liv \vv\ simple reas(tns. This point 

 was demonstrated in our last communication. 



In the case of a root heiiiLf slowlv destroved, its sensihilitv in 

 the sensil)l(> skin-area die> awav first in it> most peripherical pai-1, 

 continualh dinninshini;- further in a centripetal dii-eclion. In ordei 

 to lest this conclusion still in anothei- wav. 1 ha\ e chosen the old 

 experiment (tf compressing- the ner\ u^ uluai-is in the human body, 

 llavinu- taken the necessarv prt-caulions for secnrin<z- a precise loca- 

 lisation of the trauma. I tried this experiment twice on mvself. The 

 results, as far as I can judii-e, were in perfect accoi'dance with the 

 rule, estahlisluMi in oui' former essays. They may he descrilied as 

 follows: shoi-th aftei- the compression has heuiiu (l»y means of a 

 p(Micil put into the los>a idnai-is . paraesthesia"^ are ohserxcd, princi- 

 pally in the tops of the lourlh and liftli liuu-ei'. descending slowly 

 from thence to extend oxer the whole of the ulnar side of the 

 hand, and tinally eiidinu- in perfect inseusihilily. If the skin of th(> 

 ulnaris-area is pricked with a sharp pin in the lir>t period of th(> 

 paraeslhesias, it is experienced heyoud any <loid)t thai the pain- 

 sensalion is much less acute in the little tinker than in the latei'al 

 part of the hand. Somewhat later a new symptom may he olisei-\ed : 

 the sensation is becomin.u- distinctly dissociated. At e\ei-y renewed 

 pricking-, at lirst only a slight touch i> felt, and only a little aftei-- 

 wards a sensation of pain sets in, coiitinuing for a rathei- long 

 period. This symptom of dissociation too lias its hegimiiiig in the 

 little finger. Aftei- some lapse of time it also reaches the lateral 

 side of the hand, w hilst in the little linger it has already undergone 

 a change, the interval between the seirsation of touch and that of 

 pain having become longer, and this latter sensation greatly dinnnished. 



1) ProF. Ü. WixKLEK and Dr. G. van Hi.iNBKiiic. (»ii iuiicliou and .-i^lructin-e of 

 the li-uukdiMinaloma 1, II, 111, I'.oyal Aca<l. of Srieiices, Amsterdam 1 '.tOl --'():,' 

 and IV ibid. 1U03. 



