( 455 ) 



to BiELSCHOWSKY the total number is ±j 50,000, together with more 

 than 5000 end-bulbs and numerous cells of Merkel. 



Although he does not ascribe to the varicosities a high degree of 

 perceptibility, Botezat assumes all of them (both of the axial fibre 

 and of the rand-tibres) to be tactile discs, in accordance with most 

 authors. A difference in structure between the different tactile discs 

 or knobs he mentions without pajiug much attention to it. 



Now the facts seem to us to point to a different conclusion. 



The opinion of Bielschowsky, that the varicosities of the nerve- 

 fibres are due to "Zerfallsvorgange", seems to us to be erroneous. 

 In the first place these varicosities do not appear first in the liornj' 

 zone. On the contrary, as soon as the cells are transformed into 

 horny cells, the fibres and their varicosities degenerate, and the first 

 varicosities appear seven to eiglit layers of cells lower down. In the 

 second place the varicosities are much too regular and are distributed 

 with a far too great regularity to be the mark of degeneration, and 

 are always present in nearly the same number. In the third place 

 their structure does not point at all to "Zerfallsvorgange." 



But in his description Botezat too does not seem to have hit the 

 point. He does not give an explanation of the difference in structure 

 of the Aaricosities and of their mode of attachment to the nerve-fibres, 

 and of the fact that they are only to be found in the peripheral 

 part of the nerve-fibres and not in the basal half. 



When we treat a small piece of the snout of the mole, after fixa- 

 tion in formaline, according to the method of Bielschowsky — Pollack, 

 and study a correctly differentiated preparation in thin (6 (u) longi- 

 tudinal sections (that is a longitudinal section of the nerve-fibres and 

 of the column of cells, the section being made at right angles to 

 the surface of the epidermis of the snout), the following details will 

 be seen: the structure and form of the varicosities ("Terminalknöpfchen, 

 Seitenknöpfchen") are not the same in the course of the nei-ve-fibres. 

 When we follow a rand-fibre from the base of a column of Eimer 

 to the top, the first swellings appear at a distance of 10 to 12 cell- 

 layers from the top (fig. 1, 5). The swellings are here only loosely 

 built small nets, lying in the course of the nerve-fibres, nothing but 

 a local slackening of the bundle of neurofibrillae in the fibres, the 

 fibrillae probably forming a few anastomoses. From this point upwards 

 we see these networks appearing with great regularity in the course 

 of the nerve-fibres where the fibre passes another cell of the column, 

 and each time the reticular structure becomes finer and more 

 distinct (fig. 1, 3). 



In the upper four to five rows of cells a change in the form and 



