566 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
acetic acid has been added. The exclusion of light during the fixing 
is essential. From the mixture the tissue is transferred direct to strong 
alcohol. The hardening may require to be prolonged for 2 to 3 months. 
The staining mixture consists of 2 per cent, acetic acid solution 
100 parts, “ patentsaures Rubin ” 125 parts, and saturated picric acid 
solution in water 100 parts. In a few seconds the staining is sufficient. 
Thereafter the preparation is washed in 96 percent, alcohol. The rubin 
stain is almost insoluble in alcohol. 
Negative Staining Method for Finding Tubercle Bacilli.* * * § — M. 
Solles’ method consists in cutting up the tissue to be examined into 
small cubes, placing these in absolute alcohol for 12 hours, then in 
ether for 12 hours, and finally for an equal time in collodion. Sections, 
when made, are placed in the following fluid composed of two solutions, 
which are to be mixed just before using. (1) Aq. destill. 100*0 ; Berlin 
blue, 1*0; oxalic acid, 0*2. (2) Aq. destill. 100*0; gelatin, 1*0. All 
the anatomical elements of the tissues pick up the pigment, the micro- 
organisms remaining unstained. The author applied this method to 
the study of the morphology of the tubercle bacillus, and thinks he has 
determined the presence of spores by it. This negative staining method 
could also be applied to detect the presence of micro-organisms in 
carcinoma. 
(5) Mounting-, including- Slides, Preservative Pluids, &c. 
Mounting Medium for Algae and Fungi.f — Dr. A. A. Julien re- 
commends the following solution, an indirect outcome of Ripart and 
Petit’s formula, for mounting organisms with endoplasm of ordinary 
density, e. g. most of the filamentous Algae: — Copper chloride, 0*1 grm. ; 
copper nitrate, 0*1 grm.; chloral hydrate, 0*5 grm.; distilled water, 
just boiled, 100 * 0 ccm. The trace of acidity is removed from the solution 
in the following manner. Another solution is prepared of a few grams 
of any soluble copper salt ; to this a weak solution of caustic potash is 
added in slight excess; the hydrated copper oxide is then washed 
thoroughly, first by decantation and then upon a filter. The purified 
residue is then thrown into 100 ccm. of the preservative fluid already 
prepared, and the mixture frequently shaken at intervals until a neutral 
reaction is shown by test papers, when it is filtered. 
Spiral Springs for Manipulating Cover-glass Preparations. ;£ — 
Dr. A. A. Julien uses the spiral brass spring suggested by F. L. James, § 
for carrying cover-glass impressions. A cork encircled by the spring is 
wired to the bottom of a small round pasteboard box, and a little tuft of 
soft tissue paper or cotton wool between the edge of the inserted cover- 
slips and the side of the box prevents any dislodgment. 
The author also applies the spiral spring to staining cover-glass 
preparations. Here the spring is a straight one and made of brass or 
platinum wire. Between the coils cover-glasses, which have been 
* Le Bulletin Me'd., 1892, p. 865. See Centralbl. f. Bakteriol. u Parasitenk., 
xiii. (1893) p. 670. 
t Journ. New York Micr. Soc., ix. (1893) p. 39. 
j Tom. cit., pp. 24 and 6 (2 figs.). 
§ This Journal, 1887, p. 693. 
