ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
547 
C4) Staining- and Injecting. 
New Group of Amlin Pigments, and their Applicability to Tissue 
Staining.* — Herr H. Rosin has discovered that if saturated aqueous 
solutions of an acid and an alkaline anilin pigment be mixed so that the 
mixture have a neutral or approximately neutral reaction, a precipitate 
occurs. This precipitate is extremely bulky if the correct proportions 
have been observed, and may be partially or wholly dissolved if either 
the alkaline or acid pigment be again added in excess. These pre- 
cipitates are obtained by mixing aqueous solutions of eosin or erythrosin 
and methylen-blue, of methyl-orange and methyl-green, of rubin and 
malachite-green, of picric acid and methylen-blue or magenta-red, &c. 
All these precipitates are of a crystalline nature, and, while almost 
insoluble in water, are quite soluble in alcohol. From these solutions 
they can be re-obtained in crystalline form by concentration of the 
solutions or by the addition of water. Of all the foregoing the most 
useful is the eosin-methylen-blue mixture which makes with alcohol a 
blue-violet solution. When tissue-sections are stained with this, the 
nucleus is blue and the plasma red. Nerve-cells, however, form an 
exception ; for while the plasma stains red, the nucleus does not stain 
blue, the blue being picked up by the Nissl bodies. The neutrophile 
granules of leukhsemia stain violet. As a rule, with this pigment, 
acid substances become blue, alkaline red, neutral violet. 
New Vegetable Pigments for Microscopical Technique.! — Dr. M. 
Claudius recommends for microscopical technique stains made from 
flowers and fruits. The most suitable flowers will be found in certain 
dahlias, while the blackberry and elderberry are the most convenient 
fruits. The flowers and fruit must not be crushed, and must be quite 
fresh. The pigment is extracted by boiling in spirit and filtering when 
cold. The filtrate is inspissated by evaporating off the spirit, and then 
the strong pigment solution is diluted with water. The most suitable 
strength is found to be when 100 ccm. of pigment is prepared from 
100 grm. of fruit. The solution must now be acidulated by adding 
1 ccm. of 25 per cent, sulphuric acid to every 100 ccm. of the staining 
solution. The acid reaction is absolutely necessary, as this kind of 
vegetable stain does not work when alkaline or neutral. Ten drops of 
carbolic acid are added, and then the solution is shaken up and filtered. 
The sections are immersed in the solution for a couple of minutes, 
washed in absolute alcohol, cleared in oil of cloves, and, having been 
treated with xylol, are mounted in balsam. These vegetable stains may 
also be combined with picric acid or methyl-violet, and thus a double 
and triple staining may be imparted. To 100 ccm. of the elderberry 
stain, 5 ccm. of cold aqueous solution of picric acid are added. 
When methyl- violet is to be used in conjunction with the picric- 
acid-elderberry solution, the following procedure is advised : — (1) Stain 
with a 2 per thousand aqueous methyl-violet solution for 1-2 minutes, 
and then remove superfluous staining solution. (2) Stain for 2 minutes 
in the picric- elderberry solution, and again remove any superfluous fluid. 
* Berliuer klin. Wochenschr., 1899, No. 12. See Centralbl. Bakt. u. Par. 
l te Abt., xxvi. (1899) pp. 101-2. 
t Centralbl. Bakt. u. Par., 2 te Abt., v. (1899) pp. 579-82. 
