990 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[June li, 1873 
ol* these preparations. Extra care is directed to he 
used in the preparation of extractum conii to prevent 
the volatilization of the alkaloid this ought to contain. 
After heating the juice up to the boiling point and 
filtering, the liquor is evaporated to the proper con¬ 
sistence, either in a vacuum with the aid of heat, or 
in shallow vessels, at the ordinary temperature, by 
means of a current of air directed over the surface of 
the liquid. Extractum taraxaci, the other fresh 
extract, is prepared by slicing the root, sprinkling it 
with water and bruising, until reduced to a pulp. 
The juice is then expressed, strained, and evaporated 
in a vacuum, or in a shallow dish over a water bath, 
to the proper consistence,—it is never heated to the 
boiling point; it will thus contain all the albuminoid 
matter the fresh juice contains, if carefully prepared. 
Great care has been taken to give very minute in¬ 
structions about the preparation of each separate ex¬ 
tract, but a point that strikes one very forcibly is the 
liberal use of spirit ordered in making this class of 
preparations, and in many cases the spontaneous 
evaporation of it from the percolates in such a way 
as to materially increase the cost of the extracts so 
obtained. I am not aware whether, in the United 
States, pharmacists are liable to such a heavy duty 
upon alcohol as we are in this country, but I think 
our American cousins are wide enough awake to their 
own interests, not to permit of the “spontaneous 
evaporation” of alcohol, although the Pharmacopoeia 
may order it. 
(To be continued.) 
THE MICROSCOPE IN PHARMACY. 
BY HENRY POCKLINGTON. 
(Continued from p. 825). 
Eucalyptus Globulus.* —A remarkably beauti¬ 
ful and striking group of the Myrtacese is represented 
by the extensive genus Eucalyptus which pre¬ 
dominates to such a degree in a great part of New 
Holland that it principally determines the character 
of the vegetation of the country. The Eucalypti, 
which belong exclusively to New Holland and 
Yan Dieman’s Land, sometimes reach an enor¬ 
mous circumference, for E. globulus (Labill.) not 
unfrequently attains a height of 150 feet, while the 
trunk near the ground is from 25 to 40 feet in 
circumference. The foliage of the Eucalypti is 
very remarkable, and the sabre-like form of the 
leaves, the edges of which are turned toward the 
trunk, together with their bluish green colour, gives 
them a sombre appearance. 
In the maritime zone of Corsica, according to a 
pamphlet published by Messrs. Savory and Moore, 
the E. globulus vegetates throughout the year, and if 
the soil be suitable its growth is more rapid than 
that of any other ligneous plant. 
“Every year, in the spring, the trunk strips itself 
of a portion of its outer bark, and this bark as well 
as that which adheres to the sapwood, and even the 
leaves, when dried, preserve the characteristic odour, 
and when chewed, have a decided bitter taste, with 
an after taste of resin. The wood is hard, close, 
compact, and suited for building purposes and ship 
timber.” The bark and leaves only are used in 
pharmacy. 
* Meyen, ‘ Geography of Plant?.’ 
The bark is remarkable for the ease with which it 
separates into thin layers, whence one of its ver¬ 
nacular names of stringy bark, and is on this account 
not particularly easy of microscopical examination. 
A few hours’ maceration in cold water, and a final 
gentle boiling for five minutes will generally render 
the ligneous fibres sufficiently soft to permit the 
cutting of a thin section without tearing the softer 
tissues. Sections cut transversely radially are the 
most useful and must be very thin. 
The outer layers of the bark are corrugated layers- 
of loose cork cells covered by compressed epidermal 
cells, and in no wise remarkable. The warty eleva¬ 
tions are produced by semi-sub-epidermal receptacula, 
large very minutely porous cells, containing a mixed 
substance of great complexity, in large part proteina¬ 
ceous, the exudation of which appears to be concerned 
in the stripping off of the epidermis just referred to; 
and in part consisting of an essential oil to which the 
characteristic odour is due, and which is also found 
in similar receptacula in the leaves. The receptacula 
of the bark are best seen in transverse sections, 
treated a short time with carbon bisulphide, and 
then with iodine solution. Their size and form are 
only to be ascertained by carefully cutting thin slices 
off the epidermis, and thus exposing the receptacula 
beneath. Ether, alcohol, and carbon bisulphide 
remove the essential oil, as also alcohol, and leave 
the proteinaceous constituents which may then be 
examined by the usual reagents. Nitric acid dis¬ 
solves these and leaves a small residuum of doubtful 
character. Within these receptacula and the loose 
layer of parenchymatous cells immediately beneath the 
epidermis, are the several tissues forming the stringy 
bark. The stringiness is due to the long cord-like 
liber-tubes which are pretty evenly distributed 
amongst thin-walled, tender, parenchyma cells, 
medullary rays, and resin or oil receptacula. The 
liber-cells are tough and in bundles of six or more, 
adhere closely to each other with very slight ad¬ 
hesion to the other cells of the bark, so that very 
slight force suffices to strip the bark into layers and 
finally into fibres, whence it occurs to me, that were 
the bark cheaply obtained it might be of economic, 
value, after being exhausted of its tanning and febri¬ 
fuge qualities, for the purpose of making paper of 
great strength. 
The liber-tubes are very long and tough, porous, 
with a small central cavity containing tannic acid, a 
proteinaceus substance that intensely stains with 
solution of logwood, and also the essential oil, to- 
which probably the camphoraceous smell of the bark 
is in part due, though the oil is chiefly contained 
in large special receptacula and in the large subcu¬ 
taneous cells just described. The liber-cells are best 
studied in a radial section stained with magenta, as 
much of the dye as possible being removed with hot 
alcohol, and their pores are best examined in trans¬ 
verse logwood-stained sections. Careful use of sulpho- 
chromic acid is needful to demonstrate the successive 
ligneous deposits of the cells. 
In the cells adjoining the liber-tubes are consider¬ 
able quantities of the crystal prisms of Professor 
Gulliver, very variously shaped, and resembling those 
found in the Portugal onion. They and the liber- 
tubes are intensely doubly refractive, and, being of 
various size and shape, polarize very beautifully. So 
that a carefully-executed section from the middle of 
the bark forms an exquisitely lovely polariscope 
object, but is very difficult to mount successfully. 
