410 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Staining Elastic Fibres and the Corneous Layer of Skin."^ — Herr A. 
Koppen recommends the following method for staining elastic fibres and 
the corneous layer. The sections, freed from all foreign constituents, are 
to remain for 24 hours or longer in absolute alcohol; they are then 
placed in the following staining fluid : — Saturated alcoholic solution 
of crystal violet, 6; acid. carboL, 5; aq. destil., 100. In this 
solution, freshly made, the sections remain for 15-24 hours. They are 
then placed in iodine solution for two minutes (I, 1 ; KI, 2 ; H 2 O, 300), 
after this for five minutes in a 10 per cent, aqueous solution of common 
salt. They are then waved about for 15 seconds in 1 per cent, hydro- 
chloric acid. Next they are decolorized in absolute alcohol. When 
sufiiciently decolorized they are immersed first in turpentine and then 
in xylol, after which the sections are mounted in xylol balsam. 
Prevention of Surface Deposits in Golgi’s Chrom-silver Method.f 
— Pieces of nervous tissues which are treated by Golgi’s method are 
frequently rendered useless, owing to the thick deposit which altogether 
prevents the details of the preparation from being examined. This 
inconvenience, says Dr. E. Sehrwald, may be avoided by enveloping the 
pieces in a substance which, while it penetrates into the cavities and 
adheres closely to the surface, yet allows the silver salt to permeate 
without hindrance. Such a substance is gelatin in 10 per cent, aqueous 
solution. This, when cold, forms a firm but plastic mass, and melts at 
a temperature below that of the body. 
It is best manipulated by pouring it over the object placed in a box 
made by winding a strip of paper round a piece of cork. When cold 
the box may be immersed in the silver solution. A piece about a centi- 
metre square is quite saturated in 24 hours in the cold. 
Although fresh pieces may be imbedded in the gelatin before being 
fixed in Muller’s fluid, it is much better to envelope with gelatin after 
the Miiller. 
When the silver reaction is complete the gelatin must be removed, 
at any rate if the object is to be imbedded in paraffin. This is done 
with warm water to which chrom-silver salt, as explained above (see 
technique of Golgi’s method, p. 409), has been added to excess. The 
solubility of the gelatin is but little affected by the action of the silver 
salt or by light. 
Staining Paraffin Sections.^ — Those who have used the paraffin 
imbedding method for serial sections have, doubtless, wished for some 
simplification of the process of staining. This may be done, according 
to Dr. Kiikenthal, by dissolving the colouring matter in absolute alcohol 
and dropping the solution into turpentine until the desired depth of 
colour is secured. Sections fixed to the slide with the collodion are kept 
in the oven until the clove oil has completely evaporated, the paraffin 
dissolved in turpentine as usual, and the slide brought into the dye. 
The staining is quickly effected. Over-staining may be corrected by 
placing the slide for a short time in a mixture of acid-free absolute 
alcohol and turpentine (equal parts). Turbidity of the colouring fluid 
may be corrected by adding a drop or two of alcohol ; Meyer’s carmine, 
* Zeitschr. f. Wiss. Mikr., vi. (1880) pp. 473-5. f T. c., pp. 457-61. 
X Amer. IMou. Micr. Joiim., xi. (1890) p. 11. 
