32 THE AMERICAN MONTHLY [Jan. 



the application of Grenacher's- solution for this purpose is pub- 

 lished in 'Methods and Formulae' (Squire), 1892, and sections 

 stained as there described were exhibited by me at the Pharma- 

 ceutical Society's evening meeting in February, 1893. I have 

 recently made comparative trials by staining different kinds of 

 vegetable tissues with the solution recommended by M. 

 Radais alongside of Grenacher's solution, and another to be 

 described later. The Radais solution was certainly not quicker 

 in action, and the staining was not so good as with the other 

 two. His formula given above yields a turbid liquid, which on 

 standing for a short time deposits a considerable quantity of 

 sediment and after filtration the solution is comparatively pale 

 in color. The borax is less soluble in that strength of alcohol, 

 and therefore cannot form with carmine such a deeply colored 

 solution as with a weaker spirit. 



To test the quantity of dissolve! matter, 10c. c. of each so- 

 lution in turn was placed in a platinum basin and evaporated 

 on a water bath until the residue ceased to lose weight. The 

 precentage of alcohol is given by volume for comparison with 

 Radais formula, Grenacher's soluticm, containing 40 per c^nt. 

 (^by volume) alcohol, yielded .171 gramme. Another solution 

 (see below), containing 50 per cent, (by volume) alcohol, 

 yielded .147 gramme. Radais' solution, containing 70 per cent, 

 (by volume) alcohol, yielded .052 gramme. Borax and carmine 

 dissolve readily in the water, but when a large porportion of 

 strong alcohol is added precipitation occurs, and this takes 

 place to a considerable extent after the alcohol exceeds about 

 50 per cent, (by volume) of the whole. 



This has also a bearing on the alcohol washing after the car- 

 mine bath. If sections be placed in aqueous borax carmine, 

 or even Grenacher's solution, and after staining be trans- 

 ferred direct to 70 per cent or stronger alcohol, there is 

 danger of carmine deposits in or upon the tissues, but if excess 

 of stain be removed by just rinsing the sections in distilled 

 water previous to their removal into alcohol, the danger is re- 

 moved. It is always much safer to take this precaution, but 

 the tissues must not remain more than a few seconds in the 

 water, else the stain may be removed. 



The more strongly alcoholic solution than that known as 



