692 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
that variety of nigrosin known as alcohol-soluble nigrosin has been 
added. After-staining the sections with eosin or Kleinenberg’s hsema- 
toxylin causes the nigrosin to be replaced by either dye, leaving only 
the nucleolus of a greenish-blue colour.” 
(5) Mounting-, including: Slides, Preservative Fluids, &c. 
Reference Tables for Microscopical Work. III. Cements and 
Varnishes.* — Prof. A. B. Aubert gives the following list : — ■ 
Asphalt varnish : — Asphalt, 450 grm. ; linseed oil, 225 grm. ; tur- 
pentine, 1000 ccm. ; or dissolve asphalt in benzol and to the solution add 
gold size. In the first method, dissolve by the aid of heat ; dilute when 
necessary, with turpentine. Not very reliable as a cement. 
Bell’s cement : — Probably a solution of shellac, but the exact compo- 
sition is not known. This in the opinion of many is an excellent 
cement. 
Gold size : — Linseed oil, 25 oz. ; red lead, 1 oz. ; powdered 
white lead and yellow ochre, of each a sufficient quantity. Boil the oil 
and red lead together carefully for three hours ; pour off the clear 
liquid, and boil with a mixture of equal parts of the white lead and 
yellow ochre added in small successive portions. Let it stand, and pour 
off the clear liquid for use. 
Gram-Rutzon’s cement : — Hard Canada balsam, 50 grm. ; shellac, 
50 grm. ; absolute alcohol, 50 grm. ; anhydrous ether, 100 grm. 
The ingredients are mixed, and when the gums are dissolved, filter if 
necessary, and evaporate, away from the flame, over a water-bath until 
of a syrupy thickness. 
Gutta-percha cement (Harting) : — Gutta-percha cut in pieces, 1 part ; 
turpentine, 15 parts ; shellac, 1 part. Heat the gutta-percha and tur- 
pentine together, filter, add the shellac pulverized, and heat until a drop 
hardens on a cold glass plate. Used to attach cells; the slide must be 
warm when using the cement. 
Brown cement : — Pure gum rubber, 20 grains ; carbon disulphide, 
a sufficient quantity ; shellac, 2 oz. ; alcohol, 8 oz. Dissolve the 
rubber in the smallest possible amount of carbon disulphide, add this 
slowly to alcohol, avoiding clots ; add powdered shellac and place the 
bottle in boiling water until the shellac is dissolved and no more smell 
of carbon disulphide is given off. 
Guiacum varnish : — Gum guiacum, 2 oz. ; shellac, 2 oz. ; alcohol, 
10 oz. The powdered gum guiacum is dissolved in the alcohol 
and the powdered shellac added ; keep the bottle in hot water until all 
is dissolved. 
Shellac varnish : — 1, shellac, 60 grm. ; 2, alcohol, 60 grm. ; 3, 
castor oil, 25 grm. ; 4, alcoholic solution of anilin dye, a few drops. 1 
and 2 are dissolved and heated until quite thick, then a little of 4 is 
added, and for every 60 grm. of the mixture add 25 grm. of castor oil, 
and heat for a short time. 
Electrical cement : — 5 parts of resin ; 2 parts of hard balsam ; 1 part 
of yellow beeswax ; 1 part of red ochre. The components are melted 
together. 
Microscope, xi. (1891) pp. 150-2. 
