January 25, 1873.] THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
581 
THE MICROSCOPE IN PHARMACY. 
BY HENRY POCKLTNGTON. 
{Continued from p. 513.) 
. Nectandr.e Cortex.— This most intractable of barks 
is so nearty related to those last named that it must 
come in here. It is an exceedingly interesting bark 
and complex in structure, and it is by no means'easy 
to deal with; in fact, I do not know anything in 
the way ot wood sectionising that is more difficult 
to manage. There is this to be said, that no ordi¬ 
nary amount ot maceration will be too much for it, 
and I much question whether any amount, short 
ot a. destructive amount, would be sufficient to ren¬ 
der it sott enough for the production of a perfect 
section. Grinding down may be resorted to, but is 
tedious and unsatisfactory. For the benefit of 
those who may be disposed to try the grinding-down 
plan I will give a short account of the process. As 
thin a slice as possible should be cut, and rubbed 
smooth on one side, by grinding first on a rough stone 
and then on a hone. This surface must be cemented 
on a glass slide by Canada balsam that has been 
hardened by exposure to the air. Great care must 
be taken that no air bubbles are included between 
the surface of the section and the glass slip, or the 
section will inevitably tear away in those places and 
spoil the section. The cementing balsam should be 
kept warm until the adhesion of "bark to the slide is 
thoroughly secured, experience only will give the 
means of judging when this is, and then allow to 
cool. It it be in a proper condition the balsam will, 
when cold, be found hard enough to permit of inden¬ 
tation by the thumb nail; if less hard the section 
■will slip, if harder it may chip off. Of the two faults 
that of too much hardness is the least objectionable. 
The section is now to be rubbed upon a piece of mill¬ 
stone grit until as thin as possible without risk of 
breach of continuity, and finished upon a Canada 
oil-stone and Turkey hone successively, and finally 
mounted in balsam. This plan, be it noted, will, 
with slight modifications, apply to all hard sub¬ 
stances as bone, teeth, coal, nut-shells and the like; 
the harder the substance the better it answers. 
With nectandra bark it answers fairly well, as well 
as any plan—which, however, is not saying much— 
but the difference of hardness, shape and arrange¬ 
ments of the various constituents of the compli¬ 
cated tissue render its application difficult, and the 
results, excepting by rare good fortune, anything but 
satisfactory. Grinding down, however, will be the 
young microscopist’s only chance. The other plan 
is prolonged maceration in warm water—several 
weeks will not be too long a period ; so far as my 
experience goes, not long enough. A very strong, 
moderately sharp, and not too highly tempered 
razor (I find Mappin’s shilling razor answer admir¬ 
ably) and plenty of patience may enable one to get 
one good section out of a hundred attempts, but 
hardly a complete one, that is one right through the 
bark, ihe most hopeful direction, and fortunately 
also the most useful one, in which to cut the wood 
is longitudinally and vertically, that is from the 
bark towards the tree, but downwards. When cut 
the sections will require special treatment, and this 
is another reason why grinding down is objection¬ 
able. One section should be boiled in alcohol for a 
few seconds. The only way of doing this is to place 
the section in a shallow excavated cell with a little 
Third Series, No. 135. 
alcohol, cover it with the usual thin glass, and boil 
it o^ er a spirit lamp, adding another drop of alcohol 
vhen needed. The alcohol is then to be removed 
by blotting paper, and glycerine added. The slide is 
next to be heated to nearly the boiling-point of the 
glycerine, and retained at this temperature for a few 
minutes. It is then fit for mounting. 
A second section is to, be treated with spirit, with 
v ater, and finally with nitric acid for half a minute, 
llie acid is to be removed, the section washed with 
water (on the slide), and mounted in glycerine. A 
third section is to be treated with spirit and liquor 
potassfe, and well washed from all traces of both ; 
then thoroughly dried at a low temperature, and 
finally mounted in thick balsam, inclusion of air 
buobles being entirely disregarded. Magenta and 
sulpl 10 -chromic acid are the other most useful re¬ 
agents, but I do not know that the results gained by 
their use will compensate for the trouble in prepar¬ 
ing additional sections. 
The structure of Nectandra bark, as I have said, 
is exceeding complex. It somewhat resembles that 
of cassia, but is even more complicated, and each 
point of structure, whilst of the same type as in 
cassia, is dissimilar from the cassia tissues, so that 
whilst there is an unmistakable family likeness, 
there is a strong dissimilarity. The first thing that 
strikes one is the extent to which consolidation 
by deposition of secondary matters has gone. 
Nearly the whole tissues are thickened, the only 
exceptions, excepting the exterior cells, being resin 
receptacula and a few liber or semi-liber cells. 
The whole of the cortical structure, in fact, being 
an aggregation of Hassall’s stellate cells ; very much 
thickened, and altogether abnormal liber cells; 
thickened, variously shaped parenchyma ; and spe¬ 
cial receptacula for resin or colouring matter; these 
last also presenting novel features. 
The so-called stellate cells may be grouped as 
follows, including herein all the ordinary cortical 
cells other than liber. There are, first, the oval, 
much thickened cells of the rays of the bark. These 
have a much larger cortical cavity than the other 
cells, are porous, and the successive layers of thicken¬ 
ing substance are not easily distinguishable without 
the use of reagents. These cells are best seen in 
the balsam-mounted slide, as also are those next to- 
be mentioned, and the resin receptacula. Secondly, 
there are cells of too varied a shape to be very well 
described; all forms except oval are represented 
amongst them. Some few have a very large central 
cavity, porous of course, and are very angular. The 
majority, however, are nearly filled with the scleroge- 
nous deposits, of which the successive layers are usually 
very evident. The pores of these cells are very nu¬ 
merous ; and sometimes so fine as to give rise to 
false appearance, unless carefully illuminated. Cer¬ 
tain liber wood cells have been very peculiarly mo¬ 
dified by the pressure of the hardened stellate cells, 
and when isolated are not unlike the longer spiculse 
of some species of Gorgonia. They are thin-walled 
and not visibly porous. Other wood cells are very 
little thickened, are more or less fusiform, anti 
minutely porous. The receptacula are usually oval, 
sub-cylindrical or sub-globose cells, thin-walled, the 
walls being little affected by the colourel contents 
of the cells, and are somewhat irregularly dis¬ 
tributed. 
In conclusion, the structure of Nectandra bark is 
so exceedingly characteristic that any ordinary 
