/ 
802 SUMMARY OF CURRENT RESEARCHES RELATING TO 
In cutting, when the object slideway has been used as far as pos- 
sible, the object-holder is brought back again to the lower end, the 
screw which fixes the two cylinders is loosened, and the object is then 
brought to the desired height by 
Fig. 114. turning the screw. The cylinders 
are then again fastened, the key 
withdrawn and the cutting re- 
newed. 
(4) Staining- and Injecting-. 
Examination of Brain of Or- 
nithorhynchus. * — Dr. A. Hill 
stained the left hemisphere in 
carmine en bloc , and cut it into an 
irregular series of sections. The 
right hemisphere was treated with 
much greater care ; it was placed 
for a fortnight in a 2 per cent, 
solution of bichromate of ammonia, 
“ for even a brain which, like this 
one, has been for years in spirit, 
will yield sections which can be 
stained by Weigert’s method, if 
it is placed in a chrome-salt for a 
time.” It was next placed in 
a solution of carmine-alum for a 
week, washed in water, and after 
dehydration by alcohols of in- 
creasing strength, imbedded in celloidin. After being cut into blocks, 
a certain number of sections from each block were stained by Weigert’s 
method, in order that the arrangement of the fibre-tracts might be de- 
termined with certainty. 
Staining N erve-Tissue.f — Dr. Kaiser lays pieces of brain or spinal 
cord in Muller’s fluid for two or three days, cuts them into sections 1 to 
2 mm. thick, and leaves them for five or six days longer in the fluid. 
They are next treated for eight days with Marchi’s fluid (Muller’s fluid 
2 parts, 1 per cent, osmic acid 1 part). After washing in distilled water 
the hardening of the tissue is completed in alcohol. Sections cut in 
celloidin are laid in iron solution for five minutes, washed in Weigert’s 
haematoxylin solution, and warmed in a fresh quantity of that solution 
for a few minutes. After washing in water, differentiation is effected by 
Pal’s method ; the sections are then immediately washed in ammonia 
water to neutralize the oxalic acid. The use of a contrast stain is not 
advisable. 
Staining Connective Tissue.^ — Dr. Beneke describes a modification 
of Weigert’s fibrin method, by which the connective tissues of the most 
* Phil. Trans., 184 B (1893) p. 373. 
f Neurol. Centralbl., June 1st, 1893. See Brit. Med. Journ., No. 1706 (1893) p. 44. 
X Centralbl. f. Allgem. Path., Julv 28, 1893. See Brit. Med. Journ., No. 1705 
(1893) p. 40. 
