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a moMfication of Ibellcr^e fIDctbob of Stain=* 

 iiiQ fiDe&uUatet) Bcrve ifibrea- 



By W. Ford Robertson, M.D.* 



IN the British Medical Journal, Nov. 28th, 1896, in the course 

 of a report of a meeting of the Manchester Pathological 

 Society, a short account was given of Heller's method of 

 staining medullated nerve fibres, on the subject of which a com- 

 munication had been made by Dr. R. T. Williamson. I had for 

 some time previously been making observations on the staining 

 action of osmic acid upon nervous tissues, hardened in the chrome 

 alum-copper fluid used in Weigert's new method for neuroglia. 

 After reading the description of Heller's method, which is carried 

 out upon sections of tissue hardened in Miiller's fluid, I applied 

 the same staining process to the tissues with which I had been 

 experimenting. The results obtained were most striking, the 

 medullated fibres being deep black, and standing out with extra- 

 ordinary distinctness on a practically colourless ground. I have 

 carefully compared these preparations with others made according 

 to the original Heller's method, and there can be no question of 

 their superiority, the medullated fibres being much darker, the 

 other tissues more thoroughly bleached. It therefore seems 

 desirable to publish an account of this modification. 



Weigert's chrome alum-copper fluid is composed of: — Chrome 

 alum, 2^ per cent. ; copper acetate, 5 per cent. ; acetic acid, 5 per 

 cent. ; formalin, 10 per cent. The chrome alum is boiled in the 

 required amount of water, and when dissolved the acetic acid and 

 copper acetate are put in. The solution is filtered when cold and 

 the formalin is then added. It has recently been pointed out to 

 me that 10 per cent, is an unnecessarily large proportion of this 

 agent. It has been found that this strength prevents staining of 

 the chromatic granules of the protoplasm of the nerve-cells, and 

 that much weaker solutions harden quite satisfactorily. Probably, 

 therefore, only about 2 per cent, of formalin should be used. 

 Harden the tissues in this chrome-copper fluid for ten days or 

 longer. Prolonged action of the re-agent does not render them 

 *From the British Medical [ournaL 



