448 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
of celloidin sections is as follows : — The individual sections are lifted 
from the knife and arranged on slides 36 by 76 mm. No adhesive is 
used. When a slide is full, the superfluous spirit is removed with filter 
paper, and then each slide is wrapped round with a strip of filter paper 
which is twice the length and the same breadth as the slide. The free 
ends of the strip are lapped underneath the slide, and on the top is 
placed another (empty) slide as a sort of weight. The whole is then 
placed in a pan (10 by 5 by 3 cm.) half filled with distilled water. In this 
pan the whole lot of slides — similarly prepared — are placed, one on top 
of the other. Staining is effected by means of a dilute solution of hsemato- 
xylin, and subsequently by a 1 per cent, alcoholic solution of eosin. The 
paper strips are replaced by others previously immersed in the haemato- 
xylin solution, and the pan half-filled with tap water. Herein they re- 
main for 5-24 hours, according to the strength of the hsematoxylin 
solution and the stainability of the objects. When sufficiently stained 
the strips are replaced by clean ones, and the slides left in tap water for 
another 24 hours. They are next transferred to 95 percent, alcohol, and 
then wrapped up in strips soaked with eosin solution. After a few hours 
the slides are dried with filter paper, and, having been covered with 
fresh strips soaked in strong spirit, are transferred to 95 per cent, 
alcohol for 4-6 hours ; after which they are treated with carbol-xylol, 
and finally mounted. 
Imbedding of Tissues without hardening in Alcohol.* — Micro- 
scopical examination of animal and vegetable tissues which contain 
substances soluble in alcohol and ether is always difficult, says Dr. A. 
Dollken, and a method for obtaining thin sections is still a desideratum. 
One method, which depends on the action of aceton vapour on gum 
arabic, consists in fixing in chrom-osmium-acetic acid and picric acid 
solution. The preparation imbedded in gum is then exposed for 24 hours 
at ordinary temperature to the action of aceton vapour. This procedure, 
though possessing the advantage of not damaging certain soluble sub- 
stances, does not satisfy the principal requirement, i.e. does not produce 
sufficiently thin sections. Another procedure is to fix in formalin and 
place a piece (0*5-1 ccm.) in a capsule with 10-20 per cent, formalin, 
and then add a sufficient quantity of resorcin and some glycerin. In 
an hour’s time some drops of dilute sulphuric acid are added. In a 
short while the mass stiffens, and is sectionable in a few hours. It is 
fixed to the block or microtome plate with water-glass or syndetikon, 
and should be sectioned at once, as after a time it becomes stony 
hard. 
Very excellent results may be obtained by imbedding in soap made 
in the following way : — Castor oil or stearic acid is boiled for some time 
with 20-30 per cent, caustic soda. After having been allowed to cool and 
set, the alkali is entirely removed by pressure, dialysis, or by frequently 
dissolving the soap. The piece (about 1 cm. high) is transferred directly 
from the formalin solution to a 3-5 per cent, solution of the soap made 
with distilled water, in which it remains for 36—72 hours in a covered 
vessel. It is then solidified by evaporation, by removing the cover, or 
Zeitschr. f. wiss. Mikr., xiv. (1897) pp. 32-5. 
