the primitive axis-cyiincler, must l)e assimilated lo tiie slieadi of 

 Schwann blended with the axoplasm. These formations aie seen (o 

 get thinner and thinner and tlieir meshes to get ever wider according 

 as thej approach the terminus of the nerve. To all appearance they 

 ultimately blend or nnile with the connective tissue plasmoderms in 

 which we find the neurofibrils in the ultimate tract of their course '). 

 At tirst I was disposed to think that the described vacuolar 

 dissolution of the axis-cylinder was characteristic of the so-called 

 free nerve-endings, because 1 saw the meduUated nerves force their 

 way into the Mkissnkr corpuscles without having undergone any 

 modification. 



I can go a step farther this time, and assert on the basis of a 

 profound investigation of Meissnkr's corpuscles that tiie axis-cylinders 

 inside these corpuscles pass through precisely the same disintegration 

 process, previously described by me for the so-called free nerve- 

 endings, and just now designated as a vacuolar dissolution. 



Whereas nowadays it is maintained by many inquirers that the 

 axis-cylinder loses its medullary sheath, before it enters into the 

 corpuscles, I side with Engelmann*), Langerhans, Fischer') Key — 

 Retzius^) and Lefebure^), having been able to ascertain, in prepa- 

 rations treated with Osmic acid, that the medullary sheath, just as 

 the sheath of Schwann, is prolonged into the intracorpuscular course 

 of the nerves. Moreover my preparations also proved distinctly that 

 those medullary sheaths split up inside the sheath of Schwann exactly 

 as has been indicated above. 



I hold with Lefebure that most likely the fact that the Osmium 

 method has been abandoned for the modern tibril staining methods, 

 is responsible for the erroneous opinions about the presence or the 

 absence of medullary sheaths, prevailing in the neurological literature. 



As to the sheath of Schwann, it goes without saying that I must 

 contest the hypothesis that it passes into the formation of the capsule, 

 since to me it is an intrinsic part of the lemmoblastic sheath. (Dogiel 

 and others")). My preparations, which are well imj)regnated and of 

 good fixation also enable me to ascertain the fate of the axiscylindei's 



1) Cf. J. BoEKE. Studiën zur Nervenvegeneration I, Verli Kon. Ak. v. Wei. 

 A'dam 2e Sectie Deel, XVIII n». 6. 



«) Zeitschr. Wiss. Zool. XII 1863. 



3) Arch. f. Mikr. Anat. XII. 



*) Arch. f. Mikr. Anat. IX 1873. 



^) Revue génér. d'hislologie 1909. 



^) With more justice Langkrhaus. Krause and others assert that the sheath 

 of Schwann passes into the inner capsule of the corpuscles. 



3 



Proceedings Royal Acad. Amsterdam. Vol. XXI. 



