INTRODUCTION. xliii 



alcohol ; such a solution is the following, which has the advantage of not requiring to be filtered 

 so frequently. 



(d] Kleinenberg s Logwood Solution. Make a saturated alcoholic (70 per cent.) solution of 

 crystallised calcic chloride, and a similar solution of alum. Add 8 parts of the alum solution 

 to I of the calcic chloride. To this mixture add, drop by drop, a saturated solution of 

 hasmatoxylin in absolute alcohol, until the whole fluid assumes a deep purple colour. Use 

 only a small quantity of alcohol, as the ha^matoxylin is very soluble. The colour deepens and 

 improves by keeping. When it is desired to stain a section, this solution must be diluted by 

 adding a few drops of it to a watch-glass full of water. 



(e) Logivood solution for rapid staining. This solution, devised by E. A. Cook, yields good 

 results, but it has no advantages over any of the above. The ingredients are extract of log- 

 wood and alum, of each, 6 parts, cupric sulphate I part, and water 40 parts. Grind in a mortar 

 the alum, logwood, and cupric sulphate, all of which must be iron free, and when powdered add 

 sufficient water to form a thin paste. Leave this for one or two days, then add the remainder 

 of the water and filter. To the filtrate add a crystal of thymol, to preserve it from mould. 

 For tissues hardened in chromic acid add 8 drops of this solution to 120 drops of water, and 

 add one drop of a tenth per cent, solution of potassic bichromate just prior to use. 



CARMINE SOLUTIONS. 



Strong Carmine Solution for rapid staining. Rub up two grms. of the best carmine in a 

 mortar with a few drops of water, add 4 c.c. of liquor ammonias to dissolve the carmine, then 

 add 60 c.c. of water. Filter the solution and keep it in a stoppered bottle. The solution may 

 be diluted, if it be desired to stain a tissue slowly. 



Carmine is not employed so frequently as it used to be. A strong solution, such as the 

 above, is apt to give a somewhat uniform tinge to the section. Better results are obtained by 

 using either the above fluid diluted, or the following : 



Weak Carmine Solution. Rub up I grm. of best carmine in a mortar with a few c.c. of 

 distilled water ; add 3 c.c. of liquor ammonise, and, when the carmine is dissolved, add 1 50 c.c. 

 of distilled water, and filter into a stoppered bottle. Add 30 c.c. of glycerine and loo c.c. of 

 rectified spirit. This is a modification of Beale's carmine fluid. 



All carmine-stained preparations, after being thoroughly washed in water, are improved 

 by placing them for a few minutes in a one per cent, solution of acetic acid. This brightens 

 the colour and fixes the carmine in the nuclei, and also differentiates the stained from the 

 unstained parts. The stain thus becomes more selective. 



PICROCARMINE, OR PICROCARMINATE OF AMMONIA. 



Picrocarmine Solution. Make a solution of carmine by rubbing up i grm. of best carmine 

 with 10 c.c. of water, and adding 3 c.c. of liquor ammonise. Add this solution to 200 c.c. of a 

 cold saturated solution of picric acid. Leave the mixture exposed to the air until it evaporates 

 to one-third of its bulk. The same result may be obtained by evaporating it slowly in a hot 

 chamber, or over a water-bath at a low temperature. Filter to get rid of the precipitated 

 carmine. 



This substance was introduced by Ranvier, and is one of the most valuable dyes one can 

 employ. It is especially used for ' double staining,' containing as it does two pigments, one 

 yellow and the other red e.g. the perinuclear part of a frog's coloured blood-corpuscle is 



