August 10,1872.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
103 
tlie microscope is required, but as it is occasionally 
used in mistake for the roots of Cochlearia Armoracea, 
it is desirable that the analyst should make himself 
familiar with its structural peculiarities as compared 
with those of the latter root. Fortunately the 
structures of the two roots are as distinct as, or more 
distinct than, their botanical characteristics. The 
medulla of Aconitum Napcllus is large, angular, and 
usually well defined by a more or less dark ring. 
The medullary sheath, or more correctly, for there 
is no true sheath, vascular environment of the 
medulla is very incomplete; and the vascular bundles, 
which are small and wedge-shaped, are principally 
situate in the angles of the medulla, and are com- 
osed of tliin-walled pitted vessels, small in diameter 
with oblong transversal pitting, and of wood fibres, 
unpitted, and of long vessels, apparently transitional 
laticiferous vessels containing a dark brown (when 
the root is dry) colouring matter. The cells of the 
medulla are large, sinuous in cross section, with 
moderately thick cellulose walls, and containing great 
quantities of starch granules. The starch granules 
are aggregate in three or more, or single, variable in 
shape with a distinct punctate hilum. A very 
decided black cross is given by polarized light. The 
cells of the outer layers differ widely in shape and 
size. In the immediate neighbourhood of the 
vascular bundles they form a transitional pleuren- 
cliyma with tliick-walled cells, only partially 
attached by their parietes. The more truly paren¬ 
chymatous cells of tliis layer are ovate, slightly 
angular, thick-walled cells, with irregular parietal 
adhesion, so that numerous intercellular spaces 
exist, not only at the angles of the cells, but along 
the sides and ends, but are very minute in the latter 
position. The contents of these cells are starch 
granules imbedded in semi-albuminous (?) matter, 
which becomes deeply stained if a section be im¬ 
mersed in dilute magenta for a short time. Immer¬ 
sion in a W'eak iodine solution will be found helpful 
to the elucidation of the more difficult points in the 
structure of the cell walls and intercellular spaces 
the more so if the section be transferred from the 
iodine solution to glycerine jelly, which causes a 
slight contraction of the then deeply coloured cell 
contents, and throws the cell wall into decided 
prominence. The cuticle layers and the layers con¬ 
tiguous thereto, are much more compressed; those 
of the cuticle itself possess some interesting features, 
arising out of their number and the nature of the 
deposits on the primal membrane of the cell walls. 
Immediately below the cuticle a few liber cells are 
found entirely isolate, oval sometimes, extremely 
elliptical in cross section, and with central cavity. 
The whole of these characteristics would be dis¬ 
cernible in the scraped root if prepared for table in 
mistake for horse-radish, and most of them could be 
detected, with a little care, in partially digested con¬ 
tents of a stomach in the case of a toxological in¬ 
vestigation. 
Armohace/E Radix. — The root of Cochlearia 
Armoracea , more commonly known as horse-radish, 
is both botanically and structurally very distinct 
from the root of Aconite, the ‘ Daily Telegraph ’ 
notwithstanding. 
Medulla .—There is no true medulla, A group of 
vascular bundles probably represents an aborted 
medulla and medullary sheath. 
Wood Zone .—The wood zone is relatively very 
large and occupies upwards of two-tliirds of the 
diameter of the root. Its structure is simple and 
i easily made out. Little consolidated, or entirely 
unconsolidated, oblong, or cubic cells, a few wood 
cells, and vascular bundles enter into its composition. 
The vessels are large, much pitted, and rarely re- 
; ticulated, are distinctly cellular, the diaphragm or 
septum in some cases being unabsorbed, often only 
partially absorbed. They are arranged in bundles, 
are variable in size, and irregularly distributed. 
The oblong and cubic semi-prosencliymatous cells 
are unpitted, with no visible pores, and contain great 
quantities of starch. The wood cells are unpitted, 
often of considerable length, with central cavity, 
and are probably to be regarded as transitional 
laticiferous vessels, or wood cells acting as such. 
The starch granules are ovate or sub-ovate, some¬ 
what free in the cells and with a very limited varia¬ 
tion in size. They are very dissimilar to those of 
Aconite. 
Cortical Zone. —The cells of the cortical zone are 
according to their situation, globose, sub-globose, and 
cubic. The few liber cells present have no special 
features, and, like the cells of the bark layers, are 
strictly of the usual type. 
The chief points to be borne in mind are, the shape 
and size of the starch granules, the size, number, 
and general characters of the vascular bundles, and 
the tissue of the “ wood zone ” with the semi-pro- 
senchymatous character of its cells. 
Beiladonna: Radix. —A vascular bundle replaces 
the medulla in this root also, and consists of pitted 
vessels and wood cells. 
Wood Zone. —The wood zone possesses none of 
the usual characteristics of wood zones, except the 
presence of irregularly distributed and not numerous 
vascular bundles. The cells are parenchymatous 
excepting at the outer margin, where they become 
semi-prosencliymatous. The distribution of the 
vascular bundle is irregular, their chief aggregation 
is at the outer margin of the zone, where, elliptical in 
shape, these are arranged more regularly and form 
an interrupted ring. Thus the wood zone has 
partially the characteristics of the ordinary medulla. 
The cells of which it is in chief part composed are 
modified cylindrical cells, with somewhat tapering or 
oblique ends. They are very thin walled, excepting 
quite near the cortical layer, where they are slightly 
thickened. They suffer much change of form in 
drying, and do not wholly resume their original 
shape when re-moistened. The wood cells envelop¬ 
ing the vascular system are unpitted, with a central 
cavity. The vessels are pitted with small oval pits, 
are thin walled, not septate and imperforate, with no 
spiral fibre, discs, or reticulations. The larger cells 
of the “ wood zone,” and the cells of the cortical 
layers, contain small, or medium (rarely large) 
quantities of starch, excessively variable in shape,, 
but slightly variable in size, and with a “furrow” 
hilum and no central cavity. In certain cells the 
starch appears to be aggregated into a large compound 
granule, composed of very many granules, each of 
which suffers the usual modification of form conse¬ 
quent upon such aggregation. But tliis is probably 
entirely due to cementation with the protoplasmic 
contents of the cells, as the granules separate imme¬ 
diately upon immersion in warm water, and do not 
otherwise display the characteristics of compound 
granules. The whole of the granules give a dis¬ 
tinct cross, necessarily variable in form, by polarized, 
light. 
