Common Cavity Research Articles

SYMPHALANGISM

Symphalangism results from the failure of an interphalangeal joint to form. There may be complete or partial lack of development of the joint. When the interphalangeal joint is entirely absent, there is no dividing line between the two phalanges. Rather, they appear as a single long phalanx with a common bone marrow cavity. The trabecular structure of the bone is changed to conform to the new stresses of pull and pressure. When the interphalangeal joint has developed slightly, there are two distinct bones and two bone marrow cavities. The ligaments are shorter than normal, and there is a solid fibrous connection between the two bones. Motion is impossible. When the development of the interphalangeal joint has progressed a little further, some bending and stretching become possible. Usually one person will exhibit the various degrees of symphalangism in different fingers. Any or all of the four extremities may be involved. The

Parasternal Diaphragmatic Hernia with Report of a Case on the Right Side

Although a rapidly increasing number of cases of diaphragmatic hernia have been recorded, the publication of the following report seems to be justified as the hernia in this instance belongs to an infrequent group and presents, besides the classical symptomatology, some unusual features. According to the available literature, this is the only reported case of rightsided parasternal diaphragmatic hernia with an acquired total atelectasis of the middle lobe of the right lung. This is of importance because of the light thus thrown on the etiology of the condition. Embryology and Anatomy Before discussing the general aspects of our case it seems advisable to give a short review of the embryology of the diaphragm and of its anatomy, especially in relation to this example. In the embryo of about two weeks there is a common body cavity. A primitive diaphragm, lacking any muscle element, is formed by the fusion of the anteriorly and ventrally situated transverse septum, the dorso-1ateral pleuro-pericardial membra...

A RARE CONGENITAL DEFICIENCY OF THE PERICARDIUM

The specimen presented is that of a very rare anomaly, showing congenital absence of a separate pericardial sac, the heart being contained in the same serous cavity as the left lung. It was obtained by Dr. W. A. Burr, who was called to the city morgue to undertake the postmortem examination of a middle-aged man who had died suddenly. When the thorax was opened, Dr. Burr was surprised to find the heart and the left lung occupying a common cavity. As he realized the rarity and value of what he had found, he removed all the thoracic viscera, the diaphragm and what remained of the pleural sacs en masse and presented the specimen to the department of anatomy of the University of Toronto. REPORT OF CASE The man from whom these viscera were obtained was aged 52, of medium height and well developed. He was unmarried and lived alone and

The Development of the Embryo Sac of Smilacina stellata

1. The mother cell of Smilacina stellata divides twice to form four nuclei, which are separated by walls to form four megaspores. 2. The division walls and plasma membranes which separate the four nuclei are absorbed, so that the four reduction nuclei occupy a common cell cavity. 3. Each of these four nuclei divides again, and the resulting eight nuclei organize to form the embryo sac. 4. It is plain from these facts that we have four individual megaspore cells combining to form one embryo sac or gametophyte in Smilacina stellata. 5. It is thus strongly suggested that in the embryo sac of the lilies the first four nuclei are morphologically megaspores. 6. In Smilacina racemosa the outer daughter cell of the heterotypic division develops into the embryo sac, although the long persistence of the two nuclei formed by the division of the inner heterotypic nucleus might suggest that they should be considered a part of the embryo sac. Smilacina racemosa shows temporary cell division at the close of the homeotypic division, agreeing in this respect with Smilacina stellata.

Observations on the genus planaria

In this paper the author confines his observations to four species of the above genus, which are delineated of their natural size in an annexed drawing. They are generally clustered under leaves, stones, or pieces of wood, in slow streams; they are very rapid and change­able in their movements, in consequence of the annular muscles of which the body consists; their texture, however, is so soft, as not to admit of accurate dissection, though the author was able to ascer­tain that the body consisted of one common cavity, with lateral cells, like that of the medicinal leach. In the Planaria torva , two ventral apertures are particularly distinct. The upper one gives passage to a long flexible tube, and the lower conducts to the ovarium; this tube they frequently project, and employ it in seizing worms and aquatic insects; they also receive their food by this organ, and not exclusively by the mouth, as the author proved by presenting an earth worm to one of the Planariæ lacteæ , from winch he had re­moved the head; it soon affixed itself, and became distended by food. When, however, the animal is injured, or loses this tube, it then takes sustenance by the mouth. Though he has repeatedly seen the young of the Planaria torva and Planaria cornuta, the author has not de­termined whether they are oviparous or viviparous. The Planaria lactea and Planaria brunnea are oviparous, producing eggs within membranous capsule, each of which produces from 3 to 8 young, which, on escaping from the egg, are of various sizes, and very active. But the most singular part of the history of these animals is, that they not only perpetuate their species as above described, but also by a natural division of their body into two portions, the head part reproducing a tail, and the tail a head in about fourteen days. These appearances are represented in annexed drawings, and several experiments are detailed in further illustration of their reproduction, showing that a perfect animal is producible.

Additions to an account of the anatomy of the Squalus maximus , contained in a former paper; with observations on the structure of the bronchial artery

The author observes, that with respect to his former description of the external parts, he has no addition to make, excepting that, from the position of the fish at the time when it was drawn, a small fin was omitted between the anus and tail; which, however, is so far important, that some persons have on this ground imagined that the fish described was a different species of Squalus. Of the internal parts, the stomach is now described, and a delineation given. The liver has six ducts; but these unite, before they enter the duodenum, in one common cavity, which corresponds to the dilatation of the common duct in those quadrupeds that have no gall-bladder.