ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
551 
sections are transferred from alcohol to Lofflcr’s methylen-blue solution 
(caustic potash 1 : 10,000). They are then washed in distilled water 
and placed in the decolorizing fluid (75 parts 1/2 per cent, acetic acid and 
25 parts 1/2 per cent, watery tropaeolin 0 0). The time for decolorizing 
depends on the thickness of the sections, the thick ones requiring from 
2 to 5 seconds, the thin ones much less. The preparations are then 
thoroughly washed in distilled water ; this removes the acetic acid and 
a good deal of the stain. The sections are then put on a slide, and the 
water having been removed with blotting-paper, are dried in the air or 
over a spirit-lamp. Xylol is then dropped on and allowed to remain till 
the section is quite clear. They may now be examined or mounted in 
balsam. Oil of cloves, origanum oil, and anilin oil are not to be used. 
In this way the glanders bacilli are stained almost black, while the 
tissue is bluish. 
Staining Pathogenic Fungus of Malaria.* — Surgeon J. Fenton Evans 
has found it possible to stain the organisms of malaria with an anilinized 
alkalized solution of rosanilin hydrochloride after treatment with bi- 
chromate of potash, and after treatment with dilute sulphuric acid by an 
anilinized alkalized solution of Weigert’s acid fuchsin. Another method 
is the saturation of the tissue with a copper salt, and its reduction by 
sulphuretted hydrogen previous to coloration with anilinized alkalized 
acid fuchsin. 
Characteristics of some Anilin Dyes.f — Dr. C. Vinassa, in a contri- 
bution to “ pharmacognostic microscopy,” communicates the results of a 
number of experiments made with fifty-one different anilin pigments. 
These results are displayed in two tables. In the first are noticed the beha- 
viour to acids and alkalies, and the stain imparted to the microscopical 
preparation. Some of the dyes showed a capacity for double staining, the 
most noticeable of these being “ Solidgrun ” and “ Deltapurpurin.” By 
these the vessels were stained green and the partnchyma red. 
Many other useful staining qualities and characteristics may be 
gathered from a perusal of the table, but for these the original must 
be consulted. Table 2 gives the chemical derivation, the peculiar 
microscopical stainings of the various tissue-elements, and the behaviour 
as dyes to certain commercial products, such as silk, wool, &c. 
(5) Mounting-, including- Slides, Preservative Fluids, &c. 
Mounting Botanical Preparations in Venetian Turpentine-f — 
Herr F. Pfeiffer highly recommends Venetian turpentine for mounting 
botanical preparations, and states that it possesses qualities which render 
it capable of superseding glycerin-gelatin. On the whole, its mani- 
pulation is extremely simple. Sections of firm vegetable tissue are 
merely transferred from strong spirit (92-100 per cent.) to a drop of 
turpentine placed on a slide. After the cover-glass has been put on, 
the preparation can be ringed round. But if the sections are thin, liable 
to wrinkle up, and are to be stained, then certain eventualities have to be 
* Proc. Eoy. Soc. Lond , xlix. (1891) pp. 199-200. 
f Zeitschr. f. Wiss. Mikr., viii. (1891) pp. 34-50. 
j T. c., pp. 29-33. 
