ZOOLOGY AND BOTANY, MICROSCOPY, EtC. 
451 
Staining -Reaction of Diabetic Blood.*—Dr; L. Bretner diagnoses 
diabetes by the following procedure : — A drop of blood is spread over 
a third or half a slide, which is then incubated at 135° C. for 6 to 10 
minutes. The exact temperature is of the greatest importance. The 
slides are then stained in 1 per cent, aqueous solutions of Congo-red, 
methylen-blue, or Biebrich scarlet, or with the Ehrlich-Biondi stain. 
Immersion for 1J— 2 minutes in Congo-red stains diabetic blood barely 
or not at all, while normal blood is coloured red. Methylen-blue acts 
in a similar way, but Biebrich scarlet stains diabetic, ^but not non- 
diabetic blood. Ehrlich-Biondi solution stains diabetic blood orange* 
and non-diabetic deep violet. Successful specimens are made by means 
of contrast stains ; thus an aqueous 1 per cent, methyl-green for 1 J-2 
minutes, followed by eosin solution for 8-10 seconds, imparts a green 
hue to the diabetic blood, while the non-diabetic is red. 
(5) Mounting-, including- Slides, Preservative Fluids, &c.| 
Preservation of Pathological Preparations.! — Herr Melnikow-Ras- 
wedenkow recommends the following procedure for mounting museum 
specimens: — The fresh specimen is first treated with pure formalin, and 
after it has been sufficiently fixed with 25 per cent, spirit, the prepara- 
tion is to be mounted in solution composed of acetate of potash 30, 
glycerin 60, and distilled water 100. 
Pixation of Celloidin Sections.! — M. A. Gravis has devised the 
following procedure for fixing celloidin sections to the slide by means 
of agar. Three grm. of agar, chopped up very finely, are soaked in 
400 grm. of distilled water for a day. The mixture is then heated 
in a sand-bath and, when it has boiled for six minutes, is filtered through 
fine muslin into little bottles with wide mouths and ground glass 
stoppers. To each a small piece of camphor is added. As it cools, 
this 0*75 per cent, agar sets firm, and, though somewhat cloudy in bulk, 
is quite transparent in a thin layer. When required for use the agar 
is melted in a water-bath and a thickish layer brushed over the slide. 
Upon this the celloidin sections, immediately after removal from the 
microtome, are deposited, and then the whole series covered with 
another layer of agar. When the agar has cooled, the sections will 
be found firmly fixed. Though it is well to allow the agar to dry for 
15-30 minutes, it is not advisable to carry the evaporation too far. 
When all the slides required are prepared, they are immersed in 94 per 
cent, alcohol till the next day. This method of dehydration imparts 
a firm consistence to the agar. Next day the slides are stained, cleared 
up, and mounted. 
The foregoing procedure will allow of the prolonged action of eau 
de Javelle, of potash, of acids, but not that of distilled water, as this 
softens and swells the fixative. 
As vegetable sections need not always be stained, it is sufficient to 
* Centralbl. f. inn. Med., June 5, 1897. See Brit. Med. Journ., Epit., Aug. 28, 
3897, p. 83. 
+ Centralbl. f. allgem. Pathol, u. patkol. Anat., vii. No. 2. See Centralbl. Bakt. 
u. Par., l te Abt., xxi. (1897) p. 818. 
X Bull. Soc. Beige de Microscopic, xxiii. (1896-7) pp. 137-40. 
