488 BIELSCHOWSKY 



For other details about the toning and fixing of sections see the 

 original papers of Bielschowsky {op. cit. and Joiirn. Psychol. Neurol., 

 iv, 1904-5, p. 227), as well as Wolff (Biol. Centrbl., xxv, 1905, p. 683), 

 and Da Fang (Proc. Physiol. Soc. Journ. Physiol., liii, 1920). 



Bielschowsky states that this method is also suitable for 

 sections of celloidin or paraffin blocks of formol material, but 

 he does not recommend the practice, and we have no experience 

 of it. 



1019. Bielschowsky's Method for Peripheral Nerve-fibres 

 (Journ. Psychol. Neurol., iv, 1904-05, p. 227). This method can 

 be applied to the study of spinal and sympathetic ganglia, peri- 

 pheral nerve-endings, and end-organs in normal conditions, but 

 its chief applications belong to the domain of histopathology. 

 According to our experience good results are rarely obtained, and 

 the method requires important modifications to become as useful 

 as the above and following ones. 



The staining is carried out on sections of formol material in 

 the same way as described above. There is only this difference 

 that the staining in the ammoniacal silver bath is carried on a few 

 minutes longer, viz., until the sections have taken a decidedly 

 brown colour, after which they are washed in 10 c.c. of distilled 

 water acidified with 5 drops of acetic acid, when they acquire 

 (sometimes in a few seconds) a yellowish tinge. They should 

 then be immediately transferred into the usual 20 per cent, 

 solution of formalin. For the toning a neutral gold bath is neces- 

 sary ; sections should be left therein until red-violet. In the 

 finished preparations axis-cylinders are black, myelin red-violet, 

 connective tissue violet or blue-violet. The washing in acidified 

 water and the prolonged toning both answer for the purpose 

 of creating a sharp contrast between nerve-fibres and connective 

 tissue-fibres, which might otherwise become stained almost as 

 black as the axis-cylinders. 



I have found that counterstaining the sections for from 10 to 

 20 seconds in van Gieson's mixture before mounting serves to 

 differentiate as well as to stain the connective tissue-fibres, so 

 that thev are not so easily confused with the nerve-fibres. 

 (J. G. G.j 



Bielschowsky has also a method for central nerve-fibres. Sections 

 made by freezing from formol material are placed for twenty-four 

 hours or longer in a 4 per cent, solution of copper sulphate or 

 Weigert's mordant for neuroglia stain (§ 1083). After washing 

 they are placed for a few seconds in the usual ammoniacal silver 

 bath and then washed, reduced, toned and fixed as above. The 

 preparations are similar to those obtainable by the methods of 

 Fajerstajn, Strahiiber and Kaplan. 



1020. Bielschowsky's Method for Pieces {op. cit.). Good for 

 peripheral nerve-endings and embryonic material, and also for 



