KLEINENBERG'S H^MATOXYLIN. 99 



(" Farbsauren ") such as eosin, or " basic colouring matters"*' 

 (" Farbbasen "), may be added to the solution. 



This is one of the most important of the alum haematoxylins. 



183. Renaut's Glycerin Haematoxylm ("Glycerine Hdma- 

 toxylique"; Arch, de PhysioL, 1881, p. 640). Make a satu- 

 rated solution of alum in strong glycerin. Add drop by drop 

 about a quarter of a volume of concentrated solution of hsema- 

 toxylin in alcohol. (If you add an excess of haematoxylin the 

 liquid will become turbid, and you must then add more solu- 

 tion of alum in glycerin, until the turbidity disappears.) 

 Filter, and leave the solution exposed to the light and air for 

 some weeks, until it can be perceived by the smell that it no 

 longer contains any alcohol. Filter. 



Sections are stained in this solution in a few minutes. But 

 it can be used in another way, which is an original and really 

 valuable method. If sections, or other objects, be mounted 

 in a drop of the solution, they will, after a few weeks, be found 

 stained, and the glycerin decoloured. Such objects keep the 

 stain for years. 



Alcoholic Solutions. 



184. Kleinenberg's Haematoxylin (Quart. Journ. Hie. Sci., 

 Ixxiv, 1879, p. 208). Prepare a saturated solution of calcium 

 chloride in 70 per cent, alcohol, with the addition of a little 

 alum ; after having filtered, mix a volume of this with from 6 

 to 8 volumes of 70 per cent, alcohol. At the time of using the 

 liquid pour into it as many drops of a concentrated solution of 

 hgematoxylm in absolute alcohol as are sufficient to give the 

 required colour to the preparation of greater or less intensity, 

 according to desire. 



I find it better not to make up the staining solution at the 

 time of using, but to prepare it twenty-four or forty-eight hours 

 beforehand, so that it may " ripen " before using. 



At Naples, according to Mayer (Mitth. } ii, 1881, p. 13), the 

 solution of calcium chloride is used saturated with alum. 



Mayer further states that the object of the chloride of 

 calcium is explained by Kleinenberg to be the setting up of 

 diffusion currents between the alcohol in the tissues and the 

 external staining medium, so as to facilitate the penetration 

 of the latter. 



