532 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
isolation and pure culture, alone makes the recognition of bacillus 
tuberculi certain. 
For search of tubercle bacilli and study of the same, we have found 
a 1/10 homogeneous-immersion objective with a 2-in. eye-piece (approxi- 
mately 500 diameters) the most satisfactory and least tiring to the eye. 
A good 1/8, however, with the same eye-piece, should be quite sufficient. 
Grandmaison, F. de. — De l’emploi des solutions de chlorure de zinc pour la 
fixation des elements anatomiques. (On the use of solutions of chloride of zinc 
for fixing anatomical elements.) 
Comptes rend, hebdom. Sue. de Biol., I. (1889) No. 39. 
II o y er, H. — Ueber ein fur das Studium der directen Kerntheilung vorzuglich geeig- 
netes Object. (On an object particularly suitable for the study’of direct nuclear 
division.) Anat. Anz., V. (1890) No. 1, p. 26. 
(4) Staining and Injecting. 
Practical Notes.*— Mr. H. M. Wilder writes: — Picric Acid Staining. 
— Picrocarmine is very easily washed out with water, at any rate the 
picric acid. I prefer for that reason to stand the slide on edge, in order 
to let it drain otf, and finally touch the section (or what else) on the edge 
with blotting-paper or filtering-paper, but I do not put the blotter on 
top ; even the best, and handled most carefully, will always leave fibres. 
I then allow the section to dry a little, and finally put on the medium. 
If in balsam I let the section dry thoroughly ; the benzole balsam will 
soon clear it, without any alcohol or oil of cloves. That is for vegetable 
tissues. 
To mount Poioders. — In mounting powders I much prefer to breathe 
on the slide, press it on the dry powder, provided the firmness of the 
powder is tolerably uniform, give a few smart raps with the edge of the 
slide on the table, in order to get rid of supeifluous powder, put on the 
cover-glass, with a pencil-brush dust off the surrounding powder, and let 
the medium run under by capillary attraction in the well-known way 
with a couple of drops on the side of the cover-glass. In this way I 
seldom have any air-bubbles to contend with. 
Silicate of Sodium (soluble glass, water-glass) I would strongly 
recommend as a medium for vegetable sections and pow'ders. It “ sets ” 
quickly, less than fifteen minutes after a mount is made ; the slide can 
be cleaned with a nail-brush without fear of the cover-glass coming off. 
It clears well, and acts as its own cement, no ringing being necessary. 
Its disadvantages are : it does not agree with alcohol, ether, volatile 
oils, mucilage, acids (not even very weak), collodion ; being alkaline it 
will colour lignified tissue yellow, and alter the shades of stains more 
or less (the bluish-purple colour of haematoxylin is turned sepia-brown). 
After some time it deposits “ crystals,” that is flakes, which, while they 
detract from the beauty of the slide, cannot well mislead any one ; this 
tendency may, however, be largely obviated by using a mixture of four 
or five fluid parts of the silicate and one part of glycerin. This 
mixture is, of course, slow in drying. 
Note. — Mucilage and water-glass do not well mix, because mucilage 
is always more or less acid ; water-glass is very intolerant of acid. 
* Micr. Bull, and Sci. News, vii. (1890) p. 17. 
