ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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ribbon expand with the greatest ease, without causing any further trouble. 
The slide is next heated above a Bunsen, just enough to melt the paraffin ; 
it is then placed in a vessel containing resinified turpentine, which 
latter removes the paraffin in a few minutes ; the turpentine is removed 
by absolute alcohol, and the sections stained by any of the current 
methods, then dehydrated in absolute alcohol, cleared in resinified tur- 
pentine, and, lastly, mounted in Canada balsam dissolved in turpentine, 
as turpentine-balsam has a low refractive index.” 
C3) Cutting 1 , including Imbedding and Microtomes. 
Sharpening Ribbon-Microtome Knives.* — M. J. W. Moll says that 
the ribbon-microtome is far superior to the sliding microtome, provided 
that the knife be properly sharpened. 
After alluding to the shape of the knife, the form and dimensions of 
which are figured in his illustrations, the author says the knife is 
honed on a glass plate, 19 cm. long, 4*5 cm. broad, and the manner of 
holding the knife is depicted. The first stage consists in sharpening the 
knife on the dull side of the glass plate with emery and water, and then 
having washed it, to hone it on the smooth side of the glass, using a little 
“ chaux de Vienne.” In this way an edge quite straight and without 
any serrations is obtained, and a5ja thick section perfectly smooth, without 
a tear and showing no knife-marks, may be cut with certainty. 
To preserve Edges of Microtome Knives.f — A writer in the 
c Dental Review ’ says : — “ To render instruments perfectly aseptic, and 
to preserve the cutting edges from oxidation, they should be boiled for 
five minutes in one per cent, solution of carbonate of sodium. They 
can remain in this solution indefinitely without rusting or dulling the 
cutting edge. When required for operation they are taken out, dried 
with a sterilized piece of gauze, and handed to the operator. Whenever, 
in course of operation, they come in contact with anything not aseptic, 
all that is required to resterilize them is to dip them for a few seconds 
into the boiling solution of sodium bicarbonate.” 
C4) Staining 1 and Injecting. 
Staining of Chlorophyll.:]: — For staining the chlorophyll-bands of 
Sjpirogyra , Mr. G. Mann recommends the following process : — A glass 
vessel is filled with two litres of water, to which six drops are added of 
a 10 per cent, solution of cyanin in absolute alcohol. Then a small 
quantity of either Sjpirogyra jugalis or S. nitida is placed in the vessel, 
which is exposed to bright daylight. After some time, varying with 
the temperature of the room and the activity of the threads, from 
3-24 hours, the whole of the cyanin will have been taken up by the 
threads. The ground-substance of the chlorophyll-bands will have 
changed from a green to a bluish-green colour, while the oil-globules 
and many of the microsomes between the bands will have turned blue, 
showing their fatty nature. Concentrated solution of alcanna-root, or a 
* Botanisch Jaarboek, Gent, 1891, pp. 541-56 (1 pi.). 
f Amer. Mon. Micr. Journ., xii. (1891) p. 124. 
X Trans, and Proc. Bot. Soc. Edinb., xviii. (1889-90) pp. 394-6. 
