deal sometimes in trifles, and the smaller the organ discovered by our application, the more satisfaction have we. Should science attend only to discoveries that may be saleable in the market of practical life, where would she be standing in the present day? Among my anatomical preparations of tongues, there is one of Cynocephalus Hamadryas, and one of Tapirus Americanus, in which the arteria mediana linguæ is of very considerable size, and extends throughout the length of the tongue to apex. In Cynocephalus, it here divides into two branches, which connect themselves with the foremost twigs of the arteria profunda linguæ. I find this vessel also in the tongue of Aquila fulva. 13. On the Rami perferantes of the anterior Tibial and When an isolated injection of the anterior tibial artery is made (the trunk on the dorsum pedis must be ligatured, to prevent the filling of the tibialis posterior by the large anastomosis between these two vessels, in the first intermetatarsal interspace) some small arteries will be discovered filled in the deep layer of the calf of the leg. According to the ordinary ideas, the anterior tibial artery is only destined for the muscles, &c. on the forepart of the leg, but on a closer examination, some four or five small branches will be found, which perforate the interosseous ligament at almost equal distances, and reach the posterior part of the leg; they keep close to the periosteum, along which membrane they ramify, and they are joined by offsets of the posterior tibial, coming to the same fibrous membrane. The peroneal artery is injected with the same results; its perforating branches go across, through the interosseous ligament, to the periosteum of the anterior aspect of the tibia, and ultimately anastomise with the periosteal branches of the tibialis antica; the tibialis postica does not send off perforating branches. These communicating branches may be of some practical use in cases of ligature of either of the above-mentioned arteries: there is in my anatomical collection a preparation of the arteries of the foreleg, where a communication is kept up between the trunks of the tibialis antica and peronea, by a very stout-looking vessel of about the calibre of a raven's quill. The anastomosis takes place about half-way down the leg, and the peroneal artery is suddenly augmented in volume at the spot where the communicating branch joins the peroneal. 106 XI.-UPON A NON-STRIPED MUSCLE CONNECTED WITH THE ORBITAL PERIOSTEUM OF MAN AND Mammals, anD ON THE MUSCULUS KERATO-CRICOIDEUS. By Wm. Turner, M.B. (Lond.), F.R.S.E., Senior Demonstrator of Anatomy, University of Edinburgh. WHILST engaged in making a dissection, in the human subject, during the winter session of last year, of the superior maxillary, or second division of the fifth cranial nerve, my attention was attracted to a pale-reddish, soft, mass, filling up the narrow chink of the spheno-maxillary fissure, and extending, from the sphenoidal fissure in the sphenoid bone, to the infra-orbital canal in the superior maxillary bone. It was evidently connected to the superior (ocular) aspect of the periosteum of the orbit, and it was pierced by the orbital branch of the superior maxillary nerve, from which, as well as from the ascending branches of the spheno-palatine ganglion, it appeared to receive its supply of nerves. It completely shut off the superior maxillary nerve, with its infra-orbital continuation, from the cavity of the orbit. Since the period of making the above observation, I have availed myself of several opportunities of examining the same region in other subjects, and have constantly observed appearances, of a nature similar to those just described. The amount of the reddish mass and the depth of its tint varied slightly in different instances. Frequently, it was so pale as scarcely to attract attention, which may perhaps be the reason why it has so long been neglected by anatomists. When carefully examined with the naked eye, or, still better, with a single lens, it was seen to exhibit a fibrous appearance. A small portion snipped off with scissors, teazed out with needles, and placed on the stage of the microscope, under a quarter inch objective, was observed to be composed of pale, flattened, band-like fibres, having a faintly granular aspect, and presenting indications of elongated nuclei at intervals. From these characters I had little doubt that the structure in question consisted of the non-striped form of muscular fibre. As considerable difficulty is always experienced in obtaining for examination the contents of the human orbit, in a perfectly fresh condition, I, in the next instance, proceeded to dissect the orbits of some of the more readily obtained mammals, with a view of ascertaining if a similar structure existed in them. In the orbit of the sheep, I have most satisfactorily observed appearances which have fully confirmed the opinion of the structure already expressed. The orbit of this animal differs from that of man in possessing much less perfect walls. As a consequence of this, the orbital membrane, or periosteum, is a structure of much importance, for it stretches across the floor of Read before the Royal Physical Society of Edinburgh, Dec. 19th, 1861. That Meckel's ganglion sends branches to the periosteum of the orbit is a fact that has long been known to anatomists, though there have been difficulties in the way of giving a satisfactory reason why such an arrangement prevails. The existence of the small muscle now described, accounts for the distribution. the orbit from its outer to its inner wall, extends backwards to the optic foramen, and completes the boundary of the cavity at the spot where the bony wall is wanting. If the contents of the orbit be carefully removed, and the orbital membrane examined from above, it will be seen to be a well defined structure, distinctly fibrous, and in many places having an almost tendinous-like aspect. Intimately connected with, and forming an essential part of it, is a thin layer of a pale reddish substance, which extends across the greater part of the floor of the orbit, passing backwards to the optic foramen and sphenoidal fissure. In close contact with this structure, especially at the posterior part of the orbit, is a well-marked vascular net-work, sufficiently injected with blood to be distinctly visible. This vascular plexus constitutes a small rete mirabile, connected with the ophthalmic artery. By removing a small portion of the reddish mass, teazing it out with needles under water, and examining it with a quarter inch objective, it may be seen to be composed for the most part of flat, pale, non-striped fibres, collected together in bundles, having a faintly granular aspect and exhibiting decided indications of nuclei in their interior. These bundles of flat fibres are mingled with ordinary fibrous tissue, both white and yellow, the latter becoming more distinct after the addition of acetic acid. The pale, non-striped fibres have all the characters of the involuntary muscular fibre. Being desirous however of ascertaining if these fibres could be resolved into their constituent fibro-cells, I adopted the plan which has been recommended by Reichert, and macerated a portion of the orbital membrane for forty-eight hours in dilute hydrochloric acid. I then found that, by the aid of a very slight dissection, the fibres readily resolved themselves into the elongated fusiform cells of which they were composed. In no tissue which I have ever examined, consisting of the non-striped muscle, have I succeeded in obtaining more beautiful and more perfect specimens of the contractile fibre-cell than in this muscle of the orbital membrane. The fusiform shape of the cells, their size, and the elongated rod-like nucleus in the centre of each cell, gave to the texture a most characteristic appearance. I may also mention, that when the orbital muscle in the sheep was examined without the addition of any re-agent, besides distilled water, a number of elongated rod-like nuclei were always met with, lying free in the water surrounding the preparation, which had evidently been loosened and detached during the dissection with the needles. These nuclei corresponded in their characters to those met with in the interior of the fibro-cells. The characters which I have now enumerated render the muscular nature of the reddish texture connected with the orbital membrane sufficiently clear. On referring to the authorities who have written on the structure of the orbital membrane I find that the following opinions have been expressed concerning it. Bendz, in a paper "On the orbital membrane in the domestic Mammals," describes it as distinctly fibrous, but possessing a consi * Müller's Archiv, 1841, p. 196. derable quantity of a yellowish tissue, which he considers to be elastic, interpolated with it. He regards the opinion, which had been previously advanced by Gurlt, that the tissue was muscular, to be erroneous. Stannius* states that in those animals, in which the bony wall of the orbit is incomplete, the separation between the orbital cavity and the temporal fossa is mostly effected by a fibrous membrane, containing also abundant elastic tissue. He states that Rudolphi regarded these elastic fibres to be muscular in Bears, and that Meckel described a muscle in the orbital membrane of Ornithorynchus. Chauveau† speaks of the fibrous membrane which completes the cavity of the orbit as entirely composed of white inextensile fibres. Gurlt‡ considers it to be a strong fibrous membrane, with yellow elastic fibres interpolated. H. Müller,§ in a very brief communication, states that he has found flat muscular fibres in the inferior orbital fissure in man, and corresponding structures connected to the membrana orbitalis of mammalia. It was supposed by those, who held that the membrana orbitalis was a highly elastic and not a muscular structure, that it was through its elastic recoil that the eye-ball was re-protruded in those animals which retracted the ball through the contraction of a retractor muscle. H. Müller, again, who speaks more positively than any who have preceded him, not only of the existence of a muscle, but also of the kind of fibre of which it is composed, considers that it antagonizes those muscles which retract the eye-ball into the socket, and that thus, the reprotrusion of the globe is produced, not by a mere elastic recoil but by a muscular contraction. If this hypothesis be correct, an arrangement exists in this locality, which is certainly to be regarded as an unusual one, viz.: an involuntary muscle acting as a direct antagonist to a voluntary muscle. Whether the hypothesis be correct, or not, I am disposed to consider that the muscle has some especial relation to the vascular arrangements in the orbit. Its extension backwards to the foramina through which the orbital vessels proceed, and with which it is in immediate relation, and the very abundant vascular network found in connection with it, point, I think, to some special relation between the muscle and the vessels, a relation which is not at all inconsistent with what is known of the function of non-striped muscle in other localities. Occurrence of the Musculus Kerato-cricoideus. — In a paper, entitled "Remarks on the Musculus Kerato-cricoideus (Merkel's muscle)," published in the Edinburgh Medical Journal, February, 1860, I directed attention to an account, which had been given by Dr. Carl Merkel of Leipsic (Stimm und Sprach-Organ, 1857), of a hitherto undescribed muscle of the human larynx. Merkel described this muscle as arising from the posterior surface of the cricoid cartilage, and extending obliquely upwards and outwards to Lehrbuch der vergleichenden Anatomie, 1846, p. 401. Handbuch der Vergleich. Anat. der Haus. Säugethiere. 1860, p. 733. § Siebold and Köllikers Zeitschrift, 1858, p. 541. be attached to the posterior margin of the inferior horn of the thyroid cartilage. He stated that the muscle was not found in every larynx, and that when present it existed only on one side. In my remarks, I supplemented the description of Merkel with some additional particulars, more especially pointing out, that, although, as a rule, the muscle only occurred on one side, right or left as the case might be, yet that a double muscle might exist. I figured an example of such a bilateral muscle, which at that time was the only one I had seen. Since then I have met with two additional cases in which a double kerato-cricoid muscle was present. One of these was especially noteworthy, for the muscle, on both sides, was more largely developed than in any previous example that had fallen under my notice. The great size of the kerato-cricoid muscle was combined with a general laryngeal muscularity. The occurrence of three examples of a double kerato-cricoid muscle, during the last two years, within my own experience, shows that the bilateral arrangement is not so unusual as was in the first instance supposed. Note. Since the above paper was in type, my attention has been directed, by Professor Huxley, to a communication by H. Müller, dated Dec. 15th, 1860, entitled "On the influence of the sympathetic upon some muscles, and on the extensive occurrence of unstriped muscles in the skin in the mammalia.”* As this paper throws some additional light upon the probable action of the orbital muscle I append a short abstract of it: H. Müller, after referring to the many puzzling questions which have arisen respecting the function of the sympathetic nerve, and its relations to the muscles supplied by it, proceeds to ask two questions: 1st. Whether and which unstriped muscles are supplied by other nerves than the sympathetic? 2nd. Whether and which transversely-striped muscles are under the influence of the sympathetic? In answer to the first, the action of the oculo-motor nerve upon the unstriped fibres of the iris cannot be doubted: the vagus also acts upon unstriped muscles, and the experiments of Schiff have shown that the greater part of the vascular nerves are not connected with the sympathetic. The second question may be most effectively answered by considering the effect produced upon the eye-ball by division or irritation of the cervical sympathetic. Müller, for this purpose, refers to the experiments of Bernard, R. Wagner, and Brown-Sequard; the general tendency of which is to show, that division of the cervical sympathetic produces narrowing of the palpebral fissure, retraction of the bulb, projection of the nictitating membrane and narrowing of the anterior nares and the mouth. Irritation of the nerve by galvanization, on the other hand, produces increase of the opening of Ueber den Einfluss des Sympathicus auf einige Muskeln, &c. Von H. Müller, "Verhandlungen der Phys. Med. Gesellschaft in Würzburg.” |