80 METHODS OF MICROSCOPICAL RESEARCH. 



Allow it to stand for about six weeks, occasionally 

 shake it, when it will have obtained its greatest 

 depth of colour, then filter it once for all. It 

 will then stain in about half an hour or less and 

 does not overstain. But better results are obtained 

 by adding a few drops to an ounce of distilled water 

 and leaving the sections therein for from three to 

 four hours. It keeps well, and as it gets older, 

 stains more rapidly. If its action becomes too 

 rapid or diffuse, add more acetic acid. It may be 

 used over and over again. 



Mount in xylol balsam. 



3. WEIGERT'S FORMULA. 



(a) Hsematoxylin (Crystals), 1 gramme. 

 Absolute Alcohol, 10 c.c. 

 Distilled Water, 100 c.c. 



(b) Ferridcyanide of Potassium, 2| grammes. 

 Borax (powdered), 2 grammes. 

 Distilled Water, 100 c.c. 



Place the sections in absolute alcohol for one 

 hour then in solution (a) until they become quite 

 black then place them in distilled water for a few 

 minutes. Decolourise in solution (6) until they are 

 of a dark brown. 



This does not keep good and active beyond a few 

 months. Filter each solution every time it is used, 

 and it may be used several times. Mount in xylol 

 balsam. This is a very fine nuclear stain, and brain, 

 spinal cord, nerves, &c., are superbly stained by it. 

 It is also a splendid stain for micro-photographic 

 purposes, as the beautiful shades of brown which 

 carefully stained sections exhibit give very fine 

 photographic results. Any animal or vegetable 



