428 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
modification of Flemming’s chrom-osmium-acetic acid was very suitable 
for the purpose. The objects were placed in 60 per cent, and absolute 
alcohol for 24 hours each, after which they were imbedded in celloidin. 
The sections were fixed to the slide with Mayer’s albumen-glycerin. 
For staining purposes the Pfitzner-Flemming safranin, afterwards 
washed out with very dilute acid (0*1 to 0 • 25) gave the best results. 
A good double stain was effected with picric acid by Podwyssozki’s 
procedure. Instead of the Pfitzner-Flemming safranin, a saturated 
aqueous solution of safranin or a 1 per cent, aqueous solution of 
gentian violet, or better still, one of these followed by the other may be 
used. 
Gram’s method followed by eosin made excellent preparations, and 
these were still better if the sections were further stained with safranin. 
The chromatin granules, like the mitoses, were stained red, the achromatic 
substances a pale blue. 
(5) Mounting-, including Slides, Preservative Fluids, &c. 
Deterioration of Mayer’s Albumen-Glycerin Fixative.* — Dr. J. 
Vosseler draws attention to the fact that Maker’s albumen-glycerin is 
extremely apt to lose its adhesive property after the lapse of a few 
months. 
The loss of this essential property, its raison d'etre in fact, is usually 
accompanied by a slight browning of the colour and a decrease of the 
viscidity, and the change is so gradual that it is easily overlooked. At 
first the author was inclined to lay the blame on the corks with which 
the bottles were stopped, or on the salicylate of soda added as antiseptic. 
Both these views turned out to be untenable. Little or no effect was 
observed from using different antiseptics, the least unsatisfactory being 
camphor. After noting that the peculiar decomposition was more liable 
to take place in summer than in winter, probably from being hastened 
by the increased light, air, and temperature, the author came to the con- 
clusion that the glycerin was at the bottom of the mischief, and confirms 
his view by adducing the frequency with which preparations mounted in 
glycerin deteriorate. 
Hints for fixing Series of Sections to the Slide.t — Dr. H. Suchan- 
nek has now altogether given up the use of mica plates, and employs 
glass slides or cover- glasses. These must be perfectly clean and 
free from grease. If greasy, spirit when run over a slide shows a 
tendency to form in balls and not to spread itself out in an even layer. 
The best adhesive is Mayer’s albumen-glycerin, which is rubbed on 
the slide with the finger. The layer should be extremely thin and 
perfectly even. To this the sections will firmly adhere in about half an 
hour at a temperature of 40°. 
If the sections be thin and betray any tendency to crumpling and 
will not lie quite flat, then Gaule’s method is undoubtedly the best 
to pursue. This consists in fixing the sections with 50 per cent, neutral 
alcohol. The slides are then placed on top of an incubator with a sheet 
or two of blotting-paper interposed in order that the glass may not be 
heated above 40°. This causes the gradual and regular evaporation of 
* Zeitschr. f. Wiss. Mikr., vii. (1891) pp. 457-9. t T. c., pp. 463-6. 
