68 CLARKE, ON NERVE-FIBRE. 



In 1856, the detailed inquiries were published in a quarto 

 volume, and illustrated by figures. The doctrines, though 

 not refuted, were received with hesitation on the Continent. 

 Kollikcr speaks with caution on the subject. He says that 

 neither Stilling' s nor his own preparations have convinced 

 him that the parts described and represented are tubular 

 elements. But while he refuses to accept the " questionable 

 structure" as a normal part of the nerve-fibre, he does not 

 thereby wish to stop any further inquiry, and adds, that 

 when we consider the researches of Schultze on the olfactory 

 nerve, and those of Remak, Leydig, and Hackel on the 

 nerves of the invertebrata — researches which tend to show 

 that the contents of the nerve-tubes either wholly or partially 

 consist of fine fibres — we must be cautious in judging of state- 

 ments like those of Stilling.* Mr. Lister attempts to account 

 for this fibroid arrangement by supposing it to arise from 

 the crystallization of the fatty constituents of the white sub- 

 stance during the process of hardening; but to me it does 

 not appear to resemble anything of this description ; for in 

 form it frequently presents the appearance of a skein of 

 thread more or less loosely tangled ; whereas, in the crystalli- 

 zation of fatty substance, the fibres, however branched they 

 may be, are not twisted and curled in different directions, 

 but radiate in comparatively straight lines from a common 

 centre. 



For two years after the publication of the work already 

 mentioned, Stilling had his attention constantly directed to 

 these nerve-fibres, while engaged in his recent work, in 

 which we find him reproducing with the greatest confidence 

 the same doctrines of nerve- structure, and devoting to their 

 illustration an entire folio plate, containing no less than 

 fifty-one figures, beautifully executed, and representing the 

 appearances in question with the greatest accuracy. But 

 before I proceed to the true explanation of these appear- 

 ances, it will be better to give a little more particular account 

 of Stilling's latest descriptions, so that they may be more 

 clearly seen to admit of this explanation. 



1. The nerve-sheath consists of a thick network of the 

 finest tubules or fibres, which cross each other, communi- 

 cate, and take the most varied direction. From this thick 

 network the fibres run — many of them separately — both 



that two years earlier (1850) this anastomosis was described by myself, who, 

 so far as 1 can find, was the first to announce the fact. (' Philosophical 

 Transactions,' L851, part, ii, p. 614.) 



* ' Gcwcbelchre.' Drftte Auilagc, 1S59, p. 277. 



