ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
109 
New Test for Cellulose.* — The ordinary reagents for cellulose may 
be divided into three groups : — (1) Iodine reagents. (2) Pigments 
such as orsellin B B, which stain in acid solution. (3) Pigments such 
as Congo, benzo-purpurin, brilliant-azurin, which require an alkaline 
reaction. 
Instead of these, Sig. A. Cutolo recommends hydriodic acid of 
0*45-0 *60 Be. to be used in the following way. The specimen to bo 
examined, moistened with water or alcohol, is to be placed on a slide, 
and the excess of fluid removed by filter-paper. A few drops of the 
acid are then added and afterwards washed off. The preparation may 
now be examined ; but if permanent staining be desired, it is advisable 
to add beforehand a few drops of iodised calcium chloride solution. If 
the latter be strong, the membranes assume a violet hue ; if weak, a blue. 
Staining Gonococcus.^ — Dr. M. Weinrich advises staining Gono- 
coccus by the following method, which is really Gram plus Bismarck 
brown. The fixed dried preparation is treated with Ehrlich’s anilin- 
gentian-violet solution, or with Fraenkel’s phenol-gentian-violet solution, 
for 1-3 minutes. It is then immersed in Lugol’s iodo-potassic iodide 
solution for 1-3 minutes, after which it is decolorised in perfectly 
absolute alcohol. The alcohol must contain some crystals of cuprum 
sulph. exsicc. The last step takes from 1-1J minutes. So far, no 
water is used ; but when the Gram’s staining is finished, the preparation 
should be washed in water, and contrast stained for 2-3 minutes in the 
following solution of Bismarck brown: — Hot distilled water 70; Bis- 
marck brown 3*0 ; 96 per cent, alcohol 30; then filter. The Gonococci 
are stained brown and other bacteria violet. 
Hot Staining Bath. J — Herr Piorkowski has devised an apparatus 
for staining preparations with hot solutions. It consists of a quad- 
Fig. 25. 
rangular water -bath, the top of which is divided into square compart- 
ments for the reception of the staining fluids (see fig. 25). 
A number of preparations may be treated at the same time. Tho 
chimney serves both for filling the bath and for the escape of the steam. 
* ‘L’Orosi,’ 1897, p. 303. See Zeitschr. f. angew. Mikr., iv. (1898) p. 205. 
t Centralbl* Bakt. u. Par., l te Abt., xxiv. (1898) pp. 258-65. 
t Deutsch. med. Woclienschr., 1898, No. 20. See Centralbl. Bakt. u. Par , 
l t9 Abt., xxiv. (1898) pp. 902-3 (1 fig.). 
