ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
425 
become black. They are then washed quickly in water and transferred 
to solution 3, whereby the ganglion-cells, the neuroglia, and degenerated 
parts are quickly decolorized, the medullated fibres remaining stained 
dark violet. Finally, the sections are well washed in water, then 
dehydrated in absolute alcohol followed by carbol-xylol (3 parts xylol 
to 1 carbolic acid) and balsam. If a contrast stain bo desired, alum- 
carmine or picrocarmine or Pal’s method are recommended. 
Upson’s Gold-staining Method for Axis-cylinders and Nerve-cells.* 
— Dr. A. Mercier describes two new methods, the invention of Dr. Upson, 
of Ohio, for staining axis-cylinders and cells of central nervous system, 
the results of which are stated to be wonderful. The pieces are hardened 
in the dark for four to six months in potassium bichromate, beginning 
at 1 per cent., afterwards increased up to 2^ per cent. The hardened 
pieces are then washed in water, and after-hardened in spirit, beginning 
for the first two or three days with 50 per cent, alcohol, and ending 
with 95 per cent, spirit, until the pieces are of a greenish colour. The 
sections may bo made either with or without imbedding ; in any case 
the sections are to be thoroughly dehydrated before either method is 
applied. 
Method 1. The section is placed for one to two hours in 1 per cent, 
gold chloride solution to which 2 per cent, hydrochloric acid has been 
added. Wash in distilled water. Transfer on platinum or paper lifter 
to following solution for half a minute : — Potash, 10 per cent, solution, 
5 ccm. ; ferricyanide of potash, a trace. Wash for half a minute in 
10 per cent, potash solution. Wash well in distilled water, and transfer 
to following solution : — Acid, sulfurosum, 5 ccm. ; tinct. iodi, 3 per 
cent., 10-15 drops. Mix, and add liq. ferri chlorid., 1 drop. In this 
fluid the section is allowed to remain until it assumes a rose colour ; it 
is then thoroughly washed in distilled water, dehydrated in absolute 
alcohol, oil of cloves, and balsam. 
Method 2. The section is immersed for two hours in the following 
solution : — Gold chloride, 1 per cent., 5 ccm. ; saturated solution of 
ammonium vanadicum, 10 drops; acid, hydrochlor., 3 drops. Having 
been washed in distilled water, it is immersed for thirty to sixty seconds 
in the following mixture : — Caustic potash, 10 per cent., 5 ccm. ; ammo- 
nium vanadicum, a trace ; permanganate of potash, 10 per cent., 10 drops. 
It is again washed in distilled water, and thereupon placed in the fol- 
lowing fluid : — Tin solution, 15 drops ; aq. dest., 3 ccm. ; iron solution, 
3-5 drops ; acid, sulfurosum, 3 ccm. 
The tin solution is made by adding so much chloride of tin to 3 per 
cent, tincture of iodine until the colour is white or yellowish. The iron 
solution is a saturated solution of ferrum phosphoricum in aq. dest. 
When the section has become red it is then treated as in method 1. 
The author states that although this method may appear somewhat 
complicated, in reality it is not more cumbersome than most other pro- 
cedures, and that the results are splendid. 
Three new Methods for Staining Medullary Sheath and Axis- 
cylinder of Nerves with Hsematoxylin.f — Dr. M. Wolters describes the 
following method for staining the medullary sheath. The nerve-fibres 
* Zeitsehr. f. Wiss. Mikr., vii. (1891) pp. 474-9. f T. c., pp. 416-73. 
