410 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
until tlie grey substance assumes a brown to yellow hue and the white a 
dark grey. They are then passed through water, alcohol, and oil to 
balsam. 
Scarcely inferior to the foregoing are the pictures obtained by the 
following procedure : — The sections are placed for some minutes in a 
mixture of liq. ferri sesquiclilorati 1, H 2 0 1, spirit, rectif. 3. They are 
then immersed in the Weigert liaematoxylin solution, which must be 
removed as often as a black precipitate falls. When the sections become 
black they are washed in water and differentiated in the same way as in 
the previous method. Should they not clear up at once in the oxalic acid 
solution, the sections should be returned to the permanganate solution 
until the desired tone is obtained. After this the sections are washed 
in ammoniated water and stained with fuchsin 0*1, spirit, rectif. 100*0, 
or naphthylamin brown 1, spirit, rectif. 100, H 2 0 200. The fuchsin 
solution stains in a half to one minute, the naphthylamin brown in three 
to five minutes. The subsequent treatment is the same as in the first 
method. The medullated fibres are blue, the rest red or brown. The 
medullated fibres become dark blue or black if the haematoxylin solution 
be heated. If the differentiation be exactly hit off, the pigment, nuclear 
network, and nuclei of the ganglion cells become clearly apparent. 
Kolossow’s Osmic Acid Method.* — Dr. A. Kolossow says that since 
the last publication of his method he has made further and numerous 
trials of it, and finds that the following procedure gives the best results. 
Small pieces of tissue or organs, or even small embryos are, according to 
size, immersed for 1/2, 1, 3, 5, 8 hours in 1/2 to 1 per cent, solution of 
osmic acid, to which nitric acid has been added in the following pro- 
portion: — 5-10 drops of nitric acid to 100 ccm. of the osmic acid 
solution. They are next washed with some of the developer (a weak 
solution of pyrogallic acid) and then placed in a fresh volume of the 
developer for 10-16 hours, after which they are transferred to 85° 
spirit. The latter must be changed three or four times before the next 
step in manipulation (imbedding in paraffin) is attempted. 
Staining Fungus of Pinus sylvestris f — Herr F. Schwarz stained 
the hyphse of a fungus infesting pine trees in the following manner : — 
Sections of the affected twigs were removed from alcohol and placed for 
3-6 minutes in an old solution of Delafield’s hsematoxylin. They were 
next washed in water and then decolorized by immersing them for 1/2— 
2 minutes in 1 per cent, alcoholic oxalic acid solution. When the 
sections were reddish to the naked eye they were removed, and the 
oxalic acid thoroughly washed out in alcohol. The sections were 
mounted either in balsam or glycerin. The fungi were stained violet 
or deep-blue, while the cell-tissue of the pine appeared yellow or 
yellowish-red. 
Staining Parasitic Fungi.f — Mr. H. M. Richards recommends for 
this purpose the use of methylene-blue. A 1 per cent, solution was used, 
and the sections were stained on the slide. The sections were first 
* Zeitschr. f. wiss. Mikr., ix. (1893) p. 320. 
f S. A. a. d. Zeitschr. f. Forst- u. Jagdwesen, 1892, 10 pp. Sec Centralbl. f. 
Bakteriol. u. Parasitenk., xiii. (1893) pp. 20-1. 
% Proc. Amtr. Acad. Arts and Sei., 1893, p. 36. 
