fllMcro0copical ^ccbuiquc. 



COiMPILED BY W. H. B. 



Axis-Clylinder Stains,^ — Stroebe's yJ/^//^^^. — Stroebe describes a 

 new method of his own for staining Axis-cyUnders ; it has proved 

 serviceable in the study of nerve regeneration, and is also quite 

 satisfactory for staining the same structures within the central 

 nervous system. As the fine axis-cylinders of the young nerve 

 fibres, met with in the earliest phases of regeneration, form severe 

 test objects for stains, the present method, in Stroebe's opinion, 

 promises to be of real service. Its special feature is that a practi- 

 cally isolated stain of the axis-cyUnder is obtained. Effective 

 contrast staining is possible. The method is as follows : — (i) The 

 tissue is hardened in Miiller, thereafter, if desired, in alcohol, and 

 sections are cut as usual. ( 2) Stain in fresh saturated aqueous solu- 

 tion of anilin blue, ten minutes to one hour ; the sections become 

 blue-black in colour. (3) Wash off excess of stain in water, then 

 place in a porcelain dish of absolute alcohol, to which has been 

 added 20 to 30 drops of i per cent, solution of alkali alcohol (ig. 

 caustic potash to 100 c.c. alcohol; allow to stand twenty-four hours; 

 filter). In the alkali alcohol sections turn of a rusty-red colour, 

 clouds of reddish colouring matter issuing from them. As soon as 

 these cease to form, and the section is of a light red-brown colour 

 and transparent, differentiation is complete (one to several minutes). 

 (4) Wash in distilled water (five minutes) ; the sections acquire a 

 clear blue tint. (5) Place in the following contrast stain (a quarter 

 to half-an-hour) — concentrated aqueous solution of safranin, diluted 

 with equal parts of water. (6) Place in absolute alcohol to remove 

 excess of safranine and to dehydrate ; the section now looks 

 red with a tinge of blue, use xylol and mount in xylol-balsam. 

 Axis-cylinders appear dark blue; medullary sheaths, cell protoplasm, 

 ground substance, and cell nuclei, various shades of red. The last 

 named sometimes retain the blue colour. 



Van Gieson^s Method. — V. Kahlden has a note upon a method 

 of staining axis-cylinders and other structures of the central ner- 



* British Medical Journal^ July 29, 1893, Epitome, p. 20, from the 

 Centralbl. f. AUi^em. Path., iv., No. 2. 



