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tion, llial il lias Ikmmi proxod iiiipossihic to isolate a xciilral picM'o, 

 \\iv hrcadtli ol' wliicli is iii aiiv wav (•(»iii|);iral>l(' to that of llic 

 (loi'sai, iHiU'li less to thai ol' ihc hitcral |taiM. Vov Ihoiiuh the sti-clch- 

 hvj!: ol' Ihe lateral piece caused hv the ürowtii of ihe cone of the 

 exli'eiuities. iiiiisl he \ei'v coiisiderahle, vet it does not hecomc 

 siiflicieiillv deal' at lirsl sijihl wliv il shoidd he precisely the \-eiitral 

 parts of the dei'inalomata that remain Ihe narrowest poiMions of the 

 central area, e\'eii in the most I'ax'oraltle cases. 



^Ve Ueliexe it is in the |)ei'iplierical relations of the skin-inner- 

 vatioJi, that tlii' I'aclor will he fonnd, accoimlinü- for the fact that, 

 in f<ir<)iuiJ)lc cdscs, the lateral paii ol' Ihe derniatomala has heen 

 observed to he so much hroader than the \entral part. 



lvv[»erience has tanulit ns that cucli siinjlc jkii'I (}f the rculral arcii 

 ts sluit'hi Ik'i-diiiiiki nisi'ii'sihli' Ji-oiii lis jK'ri jilii'i'ii loiciiiils ils iiKi.tiniii iii 

 or ct'iiti'ii III , <iii(l tlnil llic ct'iifi'dl (iiu'ii (IS a inholc i/ors ihc same 

 from I'l'iitrdl loiriirds dorsdl sii/i\ and as these maxima or ceidi'a 

 correspond with tolerahle accnracy to the entrance-place ol' the 

 peri[)lierical seiisihie nerxcs, s(»me explanation is ali'eady all'oi-ded. 



The maxima Ihence woidd he those places silnaled neai'est to the 

 centnim (uaiiuiion or medidla). it' now \)\ means ofa tranma iiitlinii- 

 the nei*\"e-root, the I'i'ee condnction of stimnii is hindered, the slimidi, 

 relaininu' their actixity lonu-est, will he those that ai'c enahle(l to reach 

 ihe cenli-nm alon^' the shortest [latli from the root-reuion. This rule 

 |)r(wails lor the whole dei'inatoma as well as for each sinule part 

 of the central area. In the case of dous, where the mednlla is 

 silnaled xcry close to the hack, the distance from Nciitral skin to 

 mednlla is at least twice as larue as the distance from hack lo 

 mednlla. Kor this reason alone already, the \-enti-al part, inde|)en- 

 dently of its L^realer extension, will \)v the lirsl to h(> rednced, 

 and ihe nllimiim morieiis of the whole dernialoma will he fonnd 

 opposite the entrance-place of the dorsal skin-hranch into the doi-sal 

 piece of the cenli-al area. The lateral piece of the cent i-al area, heinu' 

 put \)\ its leiisioii into iiid'ax'orahle conditions, prohahh excn more 

 nnfa\'oral)le than those of the \-entral piece, still i-emain.-- less ill- 

 conditioned than the xcnlral piece of the central area, hecanse of 

 Ihe shorter path followed \)\ the stimuli in order to reach the 

 mednlla. In cases fax'orahle to isolaiion. il is to this latter I'actoi- that 

 we ha\(' lo look for disco\ci-inL;' the linal cause, why the lateral 

 piece remains xcry Uroad, and why the xcntral piece, its iierve- 

 |)alli heiiiü' so much ionucr, hecomes narrowed. In cases m Ma \(»rahle 

 |o isolation on the contrary, it is the other I'aclor that |tre\aiis, and 



