previously supposed to have been affected, has been submitted to examination, the remaining portion of the cord, and especially the "chorda equina," having been quite overlooked. Thirdly. Clinical observation, with a view to the establishment of physiological questions, has been, as a rule, more addressed to instances of "primary disease of the nervous centres; whereas, perhaps, more information (especially after the early effects of shock, loss of blood, injury by contusion of muscles, &c. have quite passed away*) relative to the healthy functions of certain parts of the nervous centres, would have been elicited by the study of cases of "surgical injuries" of those textures, or of such rapid diseases of the spinal or cranial bones as affect those subjacent nervous textures in a secondary manner as by pressure. This latter kind of cases is particularly serviceable in the study of the physiology and properties of the nervous centres, inasmuch as we have therein a probability of a quicker fatality, and in consequence less chance of such extensive structural changes taking place as would go far to complicate and obscure the phenomena chiefly regarded; whether such textural alterations be indeed. pathological, having occurred before death, or are essentially of post-mortem origin, and attributable in the main to chemical decomposition, which will be the more complete in proportion to ante-mortem pathological disintegration. In drawing to a close the above enumeration of omissions noticeable in many recorded cases of injury and disease, bearing upon the invaluable propositions advanced of late years in the field of our studies of the nervous system, I am anxious emphatically to repeat, that many of the shortenings of observation which I have commented upon are such as were in past years quite inevitable by reason of the uninformed state of our pathology and physiology, as regards the multifarious points connected with the nervous system. Not a few of them have been the natural consequence of the absence of any pervading and regulating theory, in support and under the influence of which, observation should have been conducted. Convincing, but yet fully capable of more extended proof, especially by means of clinical cases sedulously and minutely observed, as are the demonstrations of Dr. BrownSéquard in regard to the interesting physiological questions, of which the foregoing cases are illustrative, it is to me a subject of regret that these cases which I have just cited are so scanty in number. I was anxious, and thought I should be able in some way to show why so large a mass of material as that at my disposal has, comparatively speaking, yielded so little product, and that was my reason for bringing forward the various points of omission to which I have alluded, as occurring to one's mind in supervising clinical records in various quarters. I also felt assured that in our future investigations connected with disease and injury of the nervous system, greater care and precision of observation will be called for than hitherto we have been in the habit of bestowing in the matter. For this reason, therefore, having the hope and expectation that from their consideration a few practical suggestions may occur to the reader's mind for future use and guidapce in the prosecution of researches connected with the multiform and too often embarrassing lesions of the nervous system, I have taken this opportunity of noticing such defects in our methods of examination as rise into prominence on reflection upon the ends which in such examination we must ever keep in view. I may here opportunely draw attention to the precaution (forcibly pointed out by Dr. Brown-Séquard as being so imperative) not to be misled in our estimate of the effects of injury to nervous structures by the results almost always attendant on the division and laceration of powerful muscles, entailed in the act of obtaining access to central nervous structures, lesion of which would obviously give the appearance at first sight of nerve-paralysis. He of course alludes to experiments on the lower animals, but the hint may be taken also in respect of injuries in man, as it no doubt often happens that injury (such as laceration and contusion) of muscles from extensive accidents involving the spinal region, produces a semblance of serious lesion of some of the spinal nerves or even of the spinal cord itself. PART FOURTH. Chronicle of Medical Science. 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. EPITHELIAL SYSTEM. On the Structure of Cylindrical and Ciliated Epithelium. By Dr. N. Friedrich, of Heidelberg. The author first alludes to the observations of Kölliker and Funke upon the perpendicular markings supposed to be porous canals at the broad end of intestinal epithelium, and thought to serve the purpose of resorption of fat. He then adverts to some former observations of his own on the epithelium of the bile-ducts of the foetus, which left it doubtful whether the perpendicular markings were broadly-striped coverings of the cells or adherent cilia, and speaks of having met with cylindrical epithelium of the gall-bladder and ducts in the adult as well as in the infant, which often possessed striped terminal edges, as also of the stripings of the cell-covering in ciliated epithelium of the bronchi in man and the ox, and in the ventricles of the human brain. In the ventricles of the brain the epithelium was seen by the author to have the following striking characteristics. The cilia were seen through the homogeneous edges of the cells to pass directly into the cells more or less deeply, in some cases only just passing within, in others passing to the nuclei, and in others, but rarely, quite down to the base of the cell. In these cases each single cilium appeared to correspond to a striping of the border, and each line traversing the cells appeared to be a downward projection of a marking on the cell-cover. In many cases the cilia were adherent, so that only the striping of the border, with its continuation into the cell, could be seen; but for the most part the latter were absent, and only a simple cylindrical cell with a striped cover existed. Sometimes fat-drops were seen in or upon the threads as they pass through the cells, or at the termination of the cilia within the .cell. In some cases also the bile-tinged epithelium-cells of the gall bladder showed similar stripings, but less clearly. With regard to these observations, the author acknowledges that they are not absolutely and entirely new, as Valentint has spoken of normal ciliated epithelial cells, in which the cilia sank deeply into them; and Bühlmann,‡ Donders,§ &c., have seen cells under various conditions in the midst of which the cilia have existed, or rows of fat and granules corresponding to the striping of the bright border. The fact of the discovery of these ciliary threads in epithelial cells of bronchi, and the ependyma of cerebral ventricles as well as in the intestines and gall-ducts, quite removes the supposition that their presence is connected with the metamorphosis of fat elements. The striping of the cell-cover is connected by the author with the functions of resorption in general, as in this way we have an arrangement of lines forming a regular system of exceedingly fine capillary tubules from the tips of the cilia to the base of the cells. The author then speculates upon the connexion between the lower end of the epithelium of the empendyma *Virchow's Archiv, Band v. Hefte 5, 6, p. 535. + See article Flimmerbewegung im Handwörterbuch der Physiologie, Band i. s. 500. with the projections of the subjacent areolar-tissue cells, and on the probability of the areolartissue corpuscles being the commencement of the lymphatics; and refers to the probability of the contents of the cerebral ventricles being taken up by the termination of the ciliary threads, and carried directly into the lymph stream, the ciliary movement subserving the motion in the tubes and the onward progress of new molecular matter. The author then draws an analogy between epithelial cells and the areolar-tissue corpuscles (justifiable in certain places at least), looking upon the former as being in fact a modified instance of the latter, only destitute of any intervening substance. He proceeds to describe a species of epithelial cell which he had met with, which led him to believe that in some cases more than a single cell was placed on a common stalk communicating below by the union of their processes. Similar cells had been seen by Heidenhain in the cylindrical epithelium of the intestines of the rabbit.* The author concludes by giving the details of two cases of chronic inflammation about the brain of children, in which alterations in the epithelium were met with, and from which he is inclined to suppose that the more obvious existence of the lines seen traversing the cells is only a species of hypertrophy allied to the indistinct hypertrophy of the general ependyma of the ventricle. MUSCULAR SYSTEM. On the Minute Structure of Muscular Fibre. By Professor Amici.-The author in his communicationt describes the muscular fibre of the fly as follows. In the centre, and passing through it longitudinally, there exists a canal filled with spherical or oyal vesicles containing very fine granules. This canal is surrounded by a kind of sheath, consisting of a series of flat rings placed one above the other at a small distance, and united by numerous longitudinal threads. Close upon these threads a soft cellular tissue exists, and external to this another sheath, formed of rings united by threads. Lastly, surrounding the entire fibre we have a thin transparent wrinkled membrane. The author then describes the process of manipulation resorted to by him, and the appearances presented during the examination of such a muscular fibre. The cross stripes correspond to the profile of the flat rings of the double sheath, and consist each of three flat layers forming the thickness of a single ring; the dotting of the transverse stripes is produced by the middle one of these three layers which is punctate, whilst the two others are more transparent. The dotting is probably the result of the insertion of the longitudinal threads which bind one ring to another. Each fibre has its tendinous termination, to which it is united by ' the numerous diverging fibrils into which the tendon divides, and which are fixed to the free convexity of the last ring of the fibre. In the wing of the fly, whilst one end of the muscular fibre is so terminated by a single tendon, the other is attached by means of the diverging fibrils directly into the opaque cartilage, no single tendon intervening. Sometimes a tendinous pedicle is seen, having a bundle of fibres at its free extremity resembling a thistle flower; and very often instead of the three longitudinal bands ordinarily seen along each fibre caused by the central canal and the cellular layers, one sees only the central one. At times there is an appearance of five bands, owing to a second layer of cellular tissue near to the circumference of the muscular fibre. Unlike other fibres, those of the flaccid chest-muscles may easily be separated, and are found also to contain a number of globules or vesicles generally disposed in layers. The fibres of these muscles are very firm and cylindrical. Speaking of the voluntary muscles of higher animals, he comes to the conclusion that they are composed, not of varicose cords, nor of aggregated particles, nor of spiral threads, but of cylindrical tubules divided transversely by a diaphragm, just as the fibres of the fly are, by rings. He then alludes to the representation of muscular fibre in Mr. Quekett's treatise on the microscope, and assents entirely to the correctness of the appearances there depicted, but objects to the statement made in connexion, that the transverse lines of the fibril give the appearance as if it were composed of a linear row of more or less long or quadratic cells containing a central dark substance, which extends to the side of the cell, and prevents it being transparent. He contends that there are no cells containing the dark substance, but that the difference of light and dark portions depends in part on the difference in power of refraction of light possessed by the alternate segments of the fibrils. He then goes on to observe on the muscular fibres of the wasp, bee, and other insects. His opinion is that the contractile part of the fibre is that enclosed between the cross stripes, which during contraction or elongation remains of the same thickness. *See Moleschott's Untersuch, Band iv. Heft 3, s. 264, 1858. Il Tempo Giornale Ital. di Medicina, Chirurgia, &c., vol. ii. p. 828, quoted in Virchow's Archiv, Band xvi. Hefte 8, 4, p. 414. OSSEOUS AND CARTILAGINOUS SYSTEM. Histological character of bone produced by the Transplantation of Periosteum. By Dr. Ollier.* This observer has given the result of his experiments upon the artificial production of bones by the transplantation of periosteum, and on the regeneration of bone after resections and complete removal. These experiments, of such vast interest to physiology and surgery, were performed upon rabbits of various sizes and under various hygienic conditions, in whom he grafted portions of the periosteum into parts outside the limits of normal ossification and under the influence of vessels strange to such ossification; and he found that whenever portions of this membrane have been transplanted, exudations capable of ossification have been produced. At the end of a certain period the formation of true bone was the result, demonstrating that the periosteum is not only a mere limiting membranous envelope, and that a tissue may preserve its property and functions, although removed from the influence of all naturally surrounding parts. The author exemplifies especially the origin and mode of development of new bone, showing that if it proceeds from the periosteum it is not the result of transformation of its fibrous layers, first into cartilage and then into bone. The important element of this membrane engaged in the process is a layer of blastema on the inner surface, so delicate that in scraping the periosteum with a scalpel it is difficult to obtain any portions of it visible without the microscope; and this blastema appears as a rule to become penetrated by calcareous salts between the fourth and twelfth days (a period corresponding to the formation of the first osseous cavities), but if this process fails to occur in that period, the new bone remains in part fibrous, and the development is slow and incomplete. Insufficient nourishment, suppuration of the periosteum, and other conditions, injuriously affect the process. Without digressing further, we will here state the three kinds of experiments which the author followed in his prosecution of the question. They were as follows1stly. Those in which the portion of periosteum used was still left in more or less connexion with the bone, and was grafted into the midst of muscles or under the skin, but continuing to receive vessels from the bone. 2ndly. Those in which the pedicle of the portion of periosteum was divided three, four, or five days after transplantation, so as to interrupt all continuity with the bone. 3rdly. Those in which the piece of periosteum completely detached from the bone and rest of periosteum was at once transplanted into neighbouring or distant parts. The new bone formed in any of the above ways, varying in size according to that of the transplanted periosteum (in one case a bone almost as large as the tibia being produced), is found at its periphery to possess a regular layer of compact osseous tissue, and to be covered by its own periosteum. It is hollowed in the interior by medullary spaces, which terminate by uniting into a relatively large cavity, and which are formed by the rarification of the bone-tissue and production of small cavities, whose walls finally give way. The osseous corpuscles, as observed in delicate sections under the microscope, are seen at first to be irregularly disposed, but in the compact tissue they are arranged in layers sufficiently distinct around the vascular canals; but the regularity which in natural bone is observed around the Haversian canals is here wanting, as far as hitherto has been observed. The Haversian canals are generally parallel to the axis of the bone, but their arrangement is not perfectly intelligible in some respects. The medullary spaces are full of a soft, reddish, vascular substance, like foetal medulla, and is found to contain :-(a) Free nuclei (the médulocelles of Rohin), and small medullary cellules with a round nucleus; (b) Plates with many nuclei, generally infiltrated with fat and granulations, and containing from three to eight nuclei analogous to free nucle! (the myeloplaques of Robin; (c) Fatty matter; (d) Some fibro-plastic elements and some fibrils of connective tissue; (e) blood vessels. There very often is to be observed a peculiar longitudinal groove running all along one of the surfaces of the new bone, owing to the deficient union of the parallel borders of the portion of periosteum; a similar line is also to be observed on the surface of bone reproduced after sub-periosteal resections. The author then describes at length the method of development of bones obtained by the transplantation of periosteum, of which the following is a condensed statement:-At the very commencement an effusion of lymph takes place, at first serous and then more consistent, which infiltrates the portion of periosteum and neighbouring tissues. The periosteum soon becomes swelled, and its capillaries filled with blood, and on its inner surface an exudation is formed, which is distinguished from the above effusion by its greater consistence and by its constant increase whilst the other one decreases. At the end of four or five days an accumulation of firm, transparent, or slightly greyish material occurs within the periosteum (for its edges are then united so as to form an envelope * Brown-Séquard's Journal de Physiologie, p. 14, Jan, 1859. About the seventh for the blastema). This material is chondroid rather than cartilaginous. or eighth day the calcareous matter begins to be deposited, a process not necessarily preceded by the formation of veritable cartilage, although sometimes we find a substance hard, elastic, and with the external characters of the latter. When once commenced the ossification advances quickly, beginning at the centre and passing to the periphery. The above mentioned blastema is found by the microscope to be composed of a large number of free nuclei and cellules, analogous to those found in embryonic tissues, embedded in an amorphous, more or less granular substance. A few fusiform cellules or very fine fibrils, are also met with; and moreover cellules with a single nucleus like the small cellules of the medulla, and large regular cellules with numerous nuclei like the multi-nucleated plates of the same tissue. The blastema is more abundant in proportion to the growth of the animal. Under the transplanted periosteum this layer of blastema continues to be the germ and point of departure of new bone, the various elements being formed in succession, and the intermediate substance becoming fibroid, calcareous granulations being deposited, and ossification accomplished. In those cases in which cartilage has been found, the cellules and cavities differed from those of normal cartilage in form and grouping. The author does not appear able to account for the existence of cartilage in some cases, and its absence in others. He proceeds to detail experiments showing that neither the blood-vessels nor external layers of periosteum suffice to produce bone; a layer of blastema of embryonic cellules being necessary. These embryonic elements are seen intimately mixed at certain points with the cellular-tissue and elastic fibres composing the deep layer of periosteum. He concludes by speaking at length of the reproduction of various kinds of bone and joints after re-section, and shows that after the removal of articular extremities of two contiguous bones, the articulation is capable of regeneration if the capsule and ligaments be left continuous with the periosteum of the re-sected bone. As a means of diminishing the risk of suppurative inflammation of bone after amputation, and of forming the union of the stump, he suggests that the end of the bone should be covered, and the medullary cavity closed up, by a piece of periosteum. * On Ossification in Cartilages. By H. Müller.-The author, speaking of the so-called ossification by substitution, and not of that of secondary bone, periosteal deposits, clavical, cranial bones, &c., arrives at the following conclusions respecting the order of the phenomena of its development. 1st. That the cellules of cartilage are disposed in regular groups. 2ndly. That the fundamental substance is encrusted with calcareous salts. 3rdly. This latter is resorbed in the construction of the medullary spaces. 4thly. These increase, encroach upon the cavities of the cartilage, whose calcified walls disappear. 5thly. At the same time that the medullary spaces are so formed, the true osseous substance is deposited. 6thly. This substance, at first a soft delicate stratum, becomes hardened, and finally encrusted with calcareous matter. In this new layer many cellules are seen, of a stellate form, from the commencement. 7thly. The stellate cavities are owing to the thickening of the fundamental substance around the cellules, and not to the production of canaliculated pores in the stratified layers which exist around the calcified walls of the persistent cavities of the cartilage. 8thly. The stellated cellules of the osseous tissue are to be considered as the offshoots of the cartilage cells which, being liberated by the opening or disappearance of their capsules, are multiplied in the interior of the medullary spaces forming the foetal medulla, of which a part becomes cellulo-osseous, the other part remaining in the state of cellules of the medulla. Probably this fundamental layer is secreted by the stellate cells. The new bone is the seat of an active movement of composition and decomposition, destroying the old parts and producing new ones. 9thly. In the interior of a cartilage mass the osseous substance first appears in the canals of the cartilage. They become filled with an osteogenic layer supplied with stellated cells, at first soft, then hard, and finally encrusted with calcareous matter (as in the short bones, vertebræ, tarsal bones, &c.). 10thly. In the long bones the osseous substance is first deposited at the periphery, beneath the perichondrium, whilst the interior is transformed into fœtal medulla. GLANDULAR SYSTEM. Glandular Structures in the Conjunctiva. By Dr. W. Manz.t-the author, following Professor Meissner, who had found structures similar to the sweat-glands in the conjunctiva of *See Brown-Séquard's Journal de la Physiologie, Oct. 1858, p. 810, as quoted from Kölliker's Zeitschrift für wissenschaft. Zoologie, vol. ix. part 2, 1858. + Henle und Pfeuffer's Zeitschrift, Band v. Hefte 2, 8, p. 121. |