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SUMMARY OF CURRENT RESEARCHES RELATING TO 
left for two days, and are then transferred for twenty-four hours to a 
1 per cent, solution of iodide of potassium. The pieces are next de- 
hydrated in spirit from 80° to 96° successively, and when completely 
freed from water they are treated with chloroform and then imbedded in 
paraffin. The paraffin is removed from the sections with xylol, and these 
are then mounted in balsam. 
This method, which is extremely simple, is applicable to peripheral 
as well as central nerves; the results obtained from it are extremely 
favourable. The hue imparted by the reaction of the iodide on the 
palladium is brownish, and allows the finer structural details, both of 
nerves and nerve-cells, to be easily seen. 
Method for Staining Sections of Spinal Cord.*— Dr. R. Haug finds 
that the following method is simple and satisfactory for preparing and 
staining sections of spinal cord. 
Fresh pieces of spinal cord of half to one cm. thick are immersed for 
two days in a saturated solution of neutral acetate of copper. After 
this they are placed for one to one and a half days in a five per cent, 
solution of bichromate of potash. After washing off the superficial 
deposit of chromic acid salt, the pieces are placed in the dark in 70 per 
cent, spirit for thirty-six to forty-eight hours, then for a similar period 
in absolute alcohol. They are now ready for imbedding in paraffin or 
celloidin. The paraffin having been removed, the sections are placed in 
the following solution (hasmatoxylin 1, in alcohol 30, plus ammonia- 
alum 1 in 300 H 2 0), for fifteen to thirty minutes, or until they are of a 
deep black colour. After having been washed in water, the sections are 
toned down in muriatic acid 0*5 to 1*0, alcohol 70*0, H 2 0 30*0. 
When sufficiently decolorized (fifteen minutes at most), the now red 
sections are washed for a long time in pure water until all the acid is 
removed and the colour is blue. 
The sections may be contrast-stained by immersing them for a 
moment in undiluted neutral carmine solution, or in the following, which 
imparts a very pretty tone: — To 100 ccm. water, 0*25 carbonate of 
magnesia and 15-20 drops of liq. ammon. fort, are added. The mixture is 
heated, decanted off, and filtered. To the filtrate 0 * 59 carmine are added. 
Should Weigert’s method of differentiating be preferred, this may be 
effected by decolorizing the sections in the borax-ferricyanide of potash 
solution, and then proceeding in the usual manner. 
The author claims for his method that it is not only not very 
complicated, but that it allows of a satisfactory examination of the cord 
in a comparatively short time. 
Method for Staining the Gregarinse of Molluscum contagiosum.t 
— Dr. R. Haug recommends the following procedure for demonstrating 
the Gregarinae of Molluscum contagiosum. Fix for twenty-four hours 
in absolute alcohol, to which 1 per cent, of glacial acetic acid has been 
added. The specimen is then washed in running water for twelve hours ; 
it is now hardened again in absolute alcohol (six to twelve hours), and 
then imbedded in paraffin. The sections are first stained with haema- 
toxylin (haematox. 1 to 30 alcohol, added to ammonia-alum 1 to 300 
H 2 0). The sections are first over-stained and then differentiated with 
* Zeitscbr. f. Wiss. Mikr., vii. (1890) pp. 153-5. f T. c. , pp. 152-3 (1 pi.). 
