WEBB, ON A LOOSE CARTILAGE.
11
been completely altered, for there seems no reason to conclude
that since the raising of the tumulus, at a time when the
surface of the field was accessible, there had been such important changes in the district as would be implied by the
accumulation of a large body of water, upwards of seven feet
in depth, and the subsequent drainage of the same.
NOTES of the MICROSCOPICAL EXAMINATION of a LOOSE
CARTILAGE from the KNEE JOINT. By W. WOODHAM
WEBB, M.D., Lecturer on Histology and Minute Anatomy
at the Middlesex Hospital.
THE cartilage on which these observations were made, was
removed from the knee-joint of an elderly man in the Norfolk
and Norwich Hospital, by my friend Mr. Cadge, surgeon to
that institution. It was of somewhat larger size than is
usual in such formations, and was of a flattened and elongated shape. Its general appearance was that of a nodule of
fibro-cartilage, but the section towards the interior gave rise
to a rough gritty sensation, and showed a darker and uneven
surface. When dried, the internal parts were quite opaque,
and crumbled away if scraped.
By all the older writers it seems to have been regarded as
an established fact that the denser portions of these loose
cartilages were of true bony character; and even in Wedl
and Rokitansky, we only meet, in reference to them, with the
vague terms of ossification, cretification and calcification,
none of which convey any definite information as to the
exact histological condition of the structures, or their mode
of growth.
Before being submitted to me for examination, the specimen had been much handled and kept in dilute spirit. It
was, therefore, not in the most favorable state for ascertaining the nature of its superficial investment; but I believe
that epithelium had been present on those parts least exposed
to pressure, though on the natter portions there was no trace
cf such cells. It is only by dealing with the most delicate
preparations that any accurate knowledge of these growths can
be arrived at, and even with them a micro-chemical analysis
is necessary.
A very thin vertical section, under a power of 220, brought
into view the following appearances. On the surface was a
condensed layer of fibrous tissue which had a horizontal
disposition, and swelled up and became gelatinous with acetic
acid. This gradually lost all indications of fibrillation, and
12
WKBB, ON A. LOOSE CARTILAGE.
merged into a hyaline matter, studded with, innumerable
flattened and elongated nuclei, very closely applied to each,
other, and arranged in strata . towards the exterior, but
becoming more and more scattered and expanded as they
were traced inwards. The several stages of vacuolation and
formation of cell-spaces could now be distinguished around
these isolated nuclei, while the periplastic matter was clearer
and without any marks of definite organization. Among the
fully formed cells the usual tendency to multiplication by
division showed itself, and somewhat further in this tendency
assuming, as in ossifying cartilage, a linear direction, parallel
and perpendicular rows of cells, with but a small amount of
intervening matter, constituted the bulk of the substance.
Some of the mature cells manifested a change in the nature
of their contents. These had hitherto been clear and fluid,
with the exception of the nucleus, but now opaque granular
material began to be seen. The end-to-end cells also
coalesced with a regularity which converted them into short
tubules, closely packed together in groups. These tubules,
or many-celled spaces, soon becamefilledwith an amorphous
saline deposit to such an extent, that all traces of cell-wall
and periplastic matter were concealed, and the mass appeared
but one uniform solid block. The disintegrating and analytic
influence of reagents was here required to demonstrate the
actual condition of this reputed bone.
Dilute caustic soda, by expanding the intercellular matrix
disclosed the whole series of tubules or spaces originating in
the fused cells of which the part was made up, and so
isolated the casts about which the cell-walls were accurately
moulded. The addition of hydrochloric acid caused the
entire solution of these concretions, with effervescence, and
left exposed the empty and bare cell-walls, retaining their
perfect contour, with the nuclei still adhering in their
natural position and integrity. Longitudinal irregularities
or puckerings, produced no doubt by chemical action, gave
to these walls a sort of fibrous look. The very centre of
the mass consisted of numerous stellate groups of these
elongated spaces with cretaceous contents, round the aggregate of which were arranged the perpendicular rows of
cells undergoing the process of fusion, and filling up of
their areas.
There was no indication of nerve, vessel, bone-corpuscle,
or other structure, which could warrant the classification of
this abnormal articular growth as an osteophyte. Beyond a
certain depth from the surface, all the changes taking place
were those of retrograde metamorphosis.
SCHULTZE, ON DIATOMACE^.
13
The description follows the appearances, as seen in passing
the eye over a thin section from the circumference to the
centre.
PHENOMENA of INTERNAL MOVEMENTS in DIATOMACE^E of
the NORTH SEA, belonging to the GENERA COSCINODISCUS,
DENTICELLA, and RHIZOSOLENIA. With a Plate. By Professor MAX SCHULTZE.
THE sea around Heligoland is rich in large Diatoms,
which are frequently brought up in considerable numbers by
the fine net. Several of the species very abundant there
have been found by Ehrenberg at Cuxhaven, as Coscinodiscus, Zygoceros, Eucampia, Triceratium (fAbhandl. d. Akad.
d. Wiss. z. Berlin/ 1839). Others are still not known out
of that region, as Ch(Btoceros (Brightwell, ' Quart. Journ. of
Micr. Science/ 1856, p. 105, tab. vii), Denticella, Rhizosolenia.
By far the most numerous forms of the genus last named
occurred towards the end of the autumn. The Rhizosolenia are readily to be distinguished with the naked eye, and
were wanting on no day in the excursions undertaken in company with my father and the Messrs. G. Wagener, LieberIn a glass containing them one
kiihn, and Kupfer.
perceives, by transmitted sunlight, a glittering, proceeding
from small rods of a hair-like fineness, which refract and
bend the light, like crystals of Cholesterine, but more
strongly, so that they shine in all the colours of the rainbow.
The rods not unfrequently attain the length of 2 to 3 lines.
Perfect examples of the genus Rhizosolenia Ehrbg., so
far as I am aware, have only been found by Brightwell up to
the present, and were first mentioned in No. XX of the
' Quart. Journ. of Micr. Science/ 1857, p. 191, and were
afterwards figured in the later numbers of the same
Journal. These being all procured from the stomachs of
Ascidians and Salpse, as also from Noctiluca, were seen filled
in part with organic, but not living, contents. Still, Brightwell, in the last-mentioned place, states, from his own observation, that Rhizosolenia setigera shows a movement like
other Diatoms, in which the tubes push themselves slowly
backwards and forwards. Here also it is mentioned that
Rhizosolenise occur freely, swimming in the seas of warmer
latitudes.
Herr G. Wagener first drew my attention to the peculiar
currents of granules occurring in the Rhizosolenise, which