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PART FOURTH.

©firontcle of ifletrical ^ttentt.

HALF-YEARLY REPORT ON MICROLOGY.
By John W. Ogle, M.D., F.R.C.P.

Assistant Physician to St. George's Hospital, and Honorary Secretary to the Pathological Society.

Part I.—Physiological Micrology.

NERVOUS SYSTEM AND ORGANS OF SENSE.

Minute Anatomy of the Cerebellum and Spinal Cord. By Bcrgmann of Rostock.—The author* agrees with Bidder and Hanover as to the fact of the conical cells forming the covering of the spinal cord, passing at their smaller extremities into fibres which enter the grey substance, and there partly uniting themselves with other fibres, and partly passing into areolar tissue-cells. He adduces microscopical preparations which he has made, showing the passage of very fine fibres from the epithelium-like lining of the fourth ventnele of the toad, into the medulla. On tranverse section of this ventricle, they are seen to form arches convex in an outward direction; but the author has not noticed any union with areolar tissue in their case. Bidder, however, thought that these fibres could not form a portion of any system of nerve-fibres. Berguiann says, that in one point he was at issue with Bidder. Although, he observes, the layer out of which the fibres proceed appears to be epithelial, traces even of the cilia not failing, yet isolated fibres existed not having the character of epithelial cylinders, but of spindle cells, which project from their nucleusholding body a short process towards the ventricle, and a long one into the medulla. On looking carefully at these fibres as they lie near each other, they might be considered as limits of cells, and the nuclei as nuclei of these cells. These apparent cells are supported towards the medulla by a limitation, the fibres being united to each other by means of a delicate membrane, from which pass the tender projections. Possibly there may be between these fibres, cells, to which cilia belong. Bergmann proceeds to mention some appearances observed by him in the cerebellum of the newly-born cat when hardened by chromic acid. At the borders of very fine sections made perpendicular to the surface, a bright layer was observed between the grey substance and the pia mater, at one time more, at another less broad. This did not exist in all parts of the same thickness, but varied up to 0007 and 0008 Paris lines in thickness. This layer showed very fine lines drawn perpendicularly in such a way that in many places one might have thought it a non-nucleated cellular layer. It is in reality, however, only a delicate clear mass, penetrated by innumerable threads of great tenuity. These threads are the extreme branches of other and thinner ones which may be traced in the innermost layer of the grey substance. Here and there a nucleus was seen adherent, but it could not be made out whether or not it was intimately united to the fibre. Amidst isolated fibres were seen short branches at short angles, broken off. These had

• Henle und Ffeuffer's Zeitschrift, Band viii. Heft 2, p. 860. 40-xx. -15 partly a direction towards the periphery, and partly also into the interior of the organ: a fact adverse to the idea that the fibres pertain to the ramifications of the ganglion corpuscles. The fibres in question probably form a network in the grey substance: the end of one of them isolated could in places be seen traced into the clear substance, and separating into finer fibrils, the structure calling to mind the relation of the radial fibres of the network where they are in contact with the limitary membrane; the similarity is greater from the fact that a very fine structureless lamella, differing from the pia mater, lies on the surface of the cerebellum, representing, as it were, the limitary membrane. How far the above-named fibres enter—for instance, between the ganglion corpuscles — is not known. The author also possesses preparations from other adult animals and man. In the case of the dog, similar fibres are seen projecting out of the grey substance; the trans

Sarent layer is entirely wanting, and possibly only belongs to histological evclopment. The limitary membrane may become increased in thickness, and connected with the pia mater.

On the Nerves of the Intestinal Wall*.—G. Meissner* looks upon the areolar tissue between the muscular and the mncous coats of the intestines as one of the parts most richly supplied by nerves in the entire body. These nerves, by numerous anastomoses, form a network, the finest twigs of which appear to penetrate the muscle. The primitive fibres for the most part, and perhaps entirely, belong to the kind without any double contour, and are beset by numerous nuclei. They form the finer and thicker branchlets, and are comprised in nucleus-holding sheaths, in numbers varying from five to twenty; whilst the finest branchlets only contain from two to three primitive fibres. The small intestines appear to be the most rich in nerves, but in the walls of the stomach the nerves are very sparing. In the walls of the intestine the number of ganglia in the nervous plexuses is immense, corresponding for the most part with the thickness of the nerve-branches in which they are found; and in the small intestines almost every nerve-branch leads to a ganglion. The largest observed by the author consisted of from thirty to fifty cells; but they ordinarily contained from five to ten, having the ordinary appearance of ganglion cells. In man, pigment granules were often to be seen as contents of the cells, but in the calf they were found to be quite clear and colourless. Many of the cells were bi-polar, and this was evident whenever a single cell was seen inserted in the course of a primitive fibre without a gangb'on oeing formed. Such cells were generally spindle-shaped, and projected themselves at opposite poles into a fibre. Besides bi-polar cells, some were seen from which, either at one side or both poles, two fibres passed close to each other. The ganglia in the stomach are not relatively less than in the intestine. The ganglion cells in the stomach are larger than those of the intestinal walls. The author describes the best method of examining the nerves and ganglia of those parts, and speaks of the fresh intestine being sufficient, by the aid of acetic neid, for the examination; but inasmuch as this method is tedious, moderately concentrated pyroligneous acid affords the greatest help, which after some time makes the areolar tissue very transparent, leaving tne nerves and ganglia unaltered. After dilute pyroligneous acid has acted for some days, acetic acid proves very serviceable.

On the Olfactory Mucous Membrane of Man.—By Professor Ecker.f—The author, speaking of the septum of the nostrils, says that the very vascular succulent Schneiderian membrane is obscurely separated from the other part of the mucous membrane, poor in vessels, and of a reddish yellow colour, on which, at the upper part of the septum the olfactory nerve extends itself. This olfactory region stretches downwards about 9'" in width from the front backwards, and about \\" in a horizontal direction. This spot is distinguished from neighbouring parts by being of a yellowish colour, less transparent, aud somewhat thickened. Ecker considers this to deserve exclusively the designation of olfactory region, and calls it the "locus luteus." The undermost and most anterior part of the septal mucous membrane is covered by permanent epithelium, whilst from the line which unites the anterior free edge of the nasal bone with the anterior nasal part of the upper jaw, the ciliated form of epithelium extends upon the entire mucous membrane of the septum, with exception of the locus luteus. A definite direction of the ciliary movement could not be ascertained. Between the ciliary epithelium, measuring 0090 millimetre in length, with clear long cilia or long peduncles, other cells were seen, whose relation to them could not be defined. They were of about the same length, but for the most part broader, often swelled out, and possessing very fiue cilia. They varied at their extremities, being in some places diminished in size, and obviously closed; at other times open at their ends, euplike. But seldom was any nucleus visible within. The cells of the locus luteus consist of both these kinds. They are elongated, and below pass into a long threadlike body, which for the most part is swollen out, and often forms bulgings out, in which the so-called compensation cells (Eraatz-cellen) exist. They are very delicate and perishable. This free end is not beset by ciliated epithelium, as the author seems formerly to have thought, but their free cud contains numberless yellow pigment-granules, and it is to this colouring matter that the yellow appearance of this locus luteus is owing. The extremity of the thread-like projection bifurcates, and at the point of division oftentimes a finely granular swelling exists. Between these olfactory cells lie embedded the compensation cells. Immediately upon the surface of the mucous membrane, one comes to a layer of cells partly round, partly more irregular, and in places beset with projections, between which the root-threads of the olfactory cells sink. As regards theparietes of the nose, in the lowest and most anterior parts pavement epithelium is found, but its limits do not run parallel with that in the septum, for, proceeding from the anterior free margin of the nasal bone, it descends some lines behind the nasal part of the upper jaw, so that the anterior extremity of the lower turbinated bone, as well as the anterior part of the lower nasal cavity, are covered by this epithelium. The mucous membrane of the superior turbinated bone only in part is possessed of cilia; the spot which has none extends backwards from the covering of the nasal cavity about i'" wide, and, like the locus luteus, is coloured yellow, and contains the above-described olfactory cells; consequently it should also be considered as part of the olfactory region, which in the mammalia is much more extended, so much so, indeed, that the olfactory cells cover the entire non-ciliated olfactory region.

• ITenlc und Tfeuffer's Zeitschrift, Band viii. Heft 2, p. 284.

t Zeittchrlft flir wisaenschaftlichen Zoologie, Band viii. p. 20S: as quoted in Schmidts Jahruticher, No. 5,p. 167. 1857.

OSSEOUS AND CARTILAGINOUS SYSTEM.

Upon the Ossification of Primordial Cartilage. By A. Bauer.*—The author pursues two objects for investigation — 1. The method of origin of the peculiar structure of bone-substance out of a structure so different as cartilage; and 2. The relation between the elements of cartilage and those of bone. He speaks of the origin of all bone not antecedently cartilaginous as referriblc to the ossification of a blastema, which is generally looked upon as one of connective tissue, consisting of an indistinctly fibrillated basis, contain

• Miiller'8 Archir, No. 4, p. 347. 1857.

ing simple round cells, corresponding to the primary formative cells of areolar tissue, the future areolar tissue-corpuscles. Most probably, he continues, the ossification proceeds by the gradual formation of calcareous salts -without any distinct limitation in the inter-cellular structure, the cells developing into dentate bone-coq>uscles. The intervention of cartilage is not met with, nor any pre-existing cloudiness owing to calcareous deposit. Thus we have a direct ■ossification of areolar tissue. In the ossification of cartilage, however, the process is ntore complicated, consisting not of « mere change {UmKandlung) t)f substance, but of a total transformation {VmgetUtllnng) of" structure, which renders the investigation of their histological changes so difficult. The best method of examining is to take fine sections, made in various directions through the edge of the calcification of the diaphysis of a fresh foetal long-bone. We here see, as has been in part long known, that the cartilage cells, hitherto equally divided, assume a direction corresponding to the future bone-structure, and that m the -cartilage of long-bones they become placed in rows, which are conspicuous, on transverse section, as roundish groups. The single cells increase in Volume «t the expense of the stroma; their "contents become transparent, and show a large nucleus with nucleoli. In the walls of the cartilage cavities, or cauals, a deposit takes place of dark granular earthy elements^ and this calcareous deposit forms limits between cartilage and bone; but we as yet have not the microscopical elements of bone-substance. The cartilage cells are contained, yet unchanged, in the cartilage corpuscles, encrusted with lime, whose opaque character renders the observation of their metamorphosis difficult. In the place of a single cyst-like nucleus, more like it are found, which fill the mother-cell, and, after its dissolution, become free. It is this brood of cells, corresponding to the nucleus of the cartilage cell, which constitutes the contents of the calcified cartilage cavities, and also the starting-point of all following changes. The fact that in the ossification of •cartitage an endogenous formation of cells takes place m the ■cartBage cells—a process which is to be distinguished from the increase of cartilage ceUs by division before ossification —has hitherto been thought by observers to be connected with the formation of the medullary elements of bone, haviag, according to them, no reference to the origin of bone-substance itself: whilst, m fact, a portion of the cell-formation is covered with vessels—fat cells, or marrow cells—surrounded by a layer of soft, striped, intervening substance, which lines the inner wall of the cartilage cavities. Of pure bone-structure, nothing was hitherto to be seen: but now it forms itself for the first time by direct ossification of the blastema, by change of its cells into bone corpuscles, aud its intercellular substance into homogeneous non-granular caseous stroma.

Hence it is that the first bone-substance oocurs in the form of a canal lining each calcified cartilage cavity, which becomes obvious on a transverse section as a circle surrounded by a simple row of hone cells. This bony cylinder thickens from within outwards by successive ossification, so that each cartilage canal is gradually more or less filled by a system of concentric long lamella;. The quite uniform, concentrical arrangement of the lamellar substance of the tubules is obvious, as in the interior of each medullary canal a lamellar formation aud successive ossification from the centre outwards occur. In this way the individual hone tubules of the newly.formed bone substance must be, at first, still separated from the calcified bone-substance surrounding, and from each other. The calcified basis of the cartilage gradually passes into homogeneous bone-structure, whether the lime particles fuse into a homogeneous mass or are re-absorbed. After that, the granular lime-deposit disappears entirely, and along with it the organic structure which pertained to it; and the already-commenced resorption ot the cartilage stroma proceeds further after the removal of the lime, in order to make room for the new bone-structure. Then the single laminated bony nugs close in nearer together, until, after complete disappearance of the intervening cartilage layer, they touch each other. Hence it follows that the basis of the primordial cartilage has no part in the formation of bone-substance. This result from observation, according as it does with the chemical differences between bone-cartilage and the hyaline-cartilage substance, constitutes an objection to the theory of persistence of the latter in bone. One must therefore fall back for an explanation of the ossific process, either upon the theory of a chemical change, or that of a molecular displacement of the one substance by the other. The organic basis of bone is as httle identical with the basis of the hyaline cartilage anatomically as chemically. The last is incapable of a true ossification: its calcification is one indeed for the most part accompanying ossification, but i3, in fact, a process differing from it. The bone-substance occurring in cartilage is newly lormed in the cartilage cavities, nevertheless it does not obtain immediately as such, but there precedes it the formation of a blastema, consisting of simple cells and soft intercellular substance. This blastema accords in all relations with the ossified layer of the periosteum, and like it, must be looked upon as belonging to areolar tissue. Its ossilieatioa takes place through absorption of calcareous matter by the homogeneous intervening substance, and by the change of its cells into bone corpuscles. Also, in cartilage the ossification is preceded by the formation of areolar tissue. The part taken by the cartilage cells in the ossifie process consists in their acting as mother cells of such cells as the cartilage corpuscles- exhibit, surrounded by ossified areolar tissue and developed in a radial form. Never are the cells of the primordial cartilage changed, as such, into bone cells t they differ both in number, size, and disposition. In some places, such few bone corpuscles were' seen inside the transparent contour of a cartilage cell, that it was evident that the production of other cells by them had been Limited to but few. Fure bonesubstance is limited to the circumference of the cartilage cells, whilst this itself is surrounded by calcified, or, in rhachitic bones, by still liyaline cartilage stroma. Such appearances give rise to the assumption that the bone corpuscles correspond to the nuclei of cartilage cells, or the cartilage cell thickened by an interior deposit. This view does not hold good in the ossilieation of total cartilage. The ossifying process of the primordial cartilage has shown, on the one side, that the bone-substance, as it agrees chemically with the substance of the areolar tissue, so also, histologically, it must be referred to the elements of areolar tissue; and, on the other hand, the capability of a direct essilication must be refused to the tissue of hyaline cartilage, because neither its basis nor its cells persist, as such, in the analogous elements of bone. The proposition that a bone-formation is, in like manner, possible out of cartilage as out of areolar tissue, by deposit of calcareous matter in its basis, is, according to the author, hereby confuted; and at the same time, in his opinion, the theory of the identity of cartilage with bone and areolar tissue, which was one of the most important supports of that proposition, removed.

EPITHELIAL SYSTEM.

On the Ciliated Epithelium and Ciliary Movement in the Generative Organs of Mammalia and Man.—O. Becker,* premising the necessity of examining the inferior animals as a guide to our researches in man, and adverting, as an example, to the fact that he had been led to find ciliary epithelium in a part of the human epididymis, owing to its discovery in the pig,—proceeds to advert to the condition and character of the epithelium in various portions of the human genital organs. He first considers the female organs, and then the male organs, after birth; and afterwards he proceeds to notice the existence of ciliated epithelium in the embryo. He then enlarges upon the general subject of ciliary

• Uiitcrsuch. zu Naturlehre der Menschen unci der Thiere, Bond li. Heft 1, p. 71. 1857.

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