^34 JoifKNAL OK C<)MrAKA'll\Ji NeUROI.CXJY. 



drawbacks to Weigert's method, is thus avoided. The hard- 

 ening takes place in alcohol as usual. After imbedding in 

 celloidin and sectioning in the usual way, the sections are 

 stained in hsematoxylin dissolved in 3 per cent, acetic acid 

 solution (lOO gr. 3 per cent, acetic acid, i gr. hematoxylin in 

 absolute alcohol). The staining may occupy one to three 

 hours. The sections are then transferred to a mixture of one 

 himdred parts of saturated lithium carbonate and ten parts of 

 I per cent, ferrocyanide (red) of potassium. A larger 

 amount of the ferrocyanide hastens the washing of the stain 

 from the gray matter. The operation requires two to three 

 hours. After washing in water the sections are imbedded in 

 balsam as usual. The resulting preparation has the axis 

 cylinder fibres stained dark blue or violet and the gray matter 

 yellowish. A solution of carmine in acetic acid may be 

 used in the same way with similar results. 



3. Aluminium Sulphate Cochineal. — An accident led 

 to the discovery that the substitution of aluminium sulphate 

 for the alum called for in the formula of Czokor's alum 

 cochineal is a vast improvement. The stain not only becomes 

 more selective, acting almost solely upon the nuclei, but it 

 is more prompt and reliable and the color resulting is more 

 pronounced nnd agreeable. A similar substitution in other 

 stains using alum is suggested. 



