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CLUBBING WITH OTHER JOURNALS. We do not give a list of publications for which we will receive subscriptions in connection with Observer as too much space would be occupied, but simply state that the rate for Observer will be only $1.50 FOR 1871 When taken in connection with any other magazine, and subscription for both paid in advance at this office. E. A. L. Pathology and Microscopy. PROF. 8. A. JONES, M. D., AND PROF. D. A. COLTON, M. D, EDITORS. A REVIEW OF THE ARTICLES ENTITLED: Researches upon the development and the mode of propagation of the STRONGYLUS-GIGAS. BY M. G. BALBIANI. TRANSLATED FROM THE FRENCH BY D. A. COLTON M. D. From the Journal de L'Anatomie et de La Physiologie normales et Pathologiques de L'Homme et des Animaux. Public par M. CHARLES ROBIN. M. Balbiani, in his experiments, honorably professes to follow in the way inaugurated by Dujardin, Siebold, Meissner, VanBeneden and Küchnmeister. Among his co-laborers he gives the first place to M. Davaine in France, and Leuckart in Germany. The past history of the Strongylus has been almost exclusively confined to its anatomy; and this too of specimens that had been some time in alcohol. There has been no precise description of its development or of its mode of transmission. M. Davaine inquires whether the Strongylus, may be oviparous or viviparous; but inclines to the former. He, consequently, does not place much confidence in Wedel's assertion that he had seen one of these animals filled with little worms. Messrs Schneider and Leuckart, from certain observations which they made, concluded that the Strongylus was subject to certain migrations; and that, by the use of fish, it was introduced into the organism of superior animals, where it was nurtured in its definite form. M. Balbiani coincides with the opinion of these two eminent German helminthologists and thinks that such opinion accords with experimental observations. In November 1867 Mr. Gréhant, of the College of France, presented to Balbiani three specimens of the Strongylus that were taken from the abdominal cavity of a dog upon which some physiological experiments were being made. They consisted of two males and one female. The female was over thirty inches long and weighed some forty grains; the males were each about ten inches in length; one weighing a little more, and the other a little less than three grains. These worms lived in the air for some three hours after their extraction, and executed quite lively movements; especially, during the first portion of that time (1.) (1) The kidneys of the dog were found to be perfectly healthy, and consequently if the worms ever inhabited those organs, they must have escaped when very young. On pressing the body of the female, near the genital orifice, a brownish liquid escaped in sufficient quantity to stain the fingers on drying. This contained numerous ova as shown by the microscope; but by introducing a tapering tube into the orifice of the vulva, the eggs were obtained from the uterus, in sufficient quantity, to enable one to observe their development, and to institute experiments in reference to the mode in which the Strongylus is transmitted. The egg of the strongylus gigas is ellipsoid in form, somewhat diminished toward the two poles. It measures one-four hundredth of an inch (Omm,068) in its greater diameter, and near one-six hundred-twenty-fifth of an inch (0mm,042) in its lesser. The shell is formed of a chorion which is thick but fragile, transparent, and of a brown color, except at the two extremities, where it is colorless. It is thicker at the latter points, but more fragile than the middle portion, so that the contents escape at one of the poles when the shell is compressed. The middle portion is pierced by a great number of minute funnel shaped openings, the orifices of which, appear as clear spaces upon the brown portion with which they are bordered. Within this first envelope is the vitelline membrane which is closely applied to the internal wall of the shell. In all of the eggs taken from the uterus of the female, this membrane touched the vitellus only in the middle portion of the egg, while, at the extremities, it was separated by a space sufficiently large to admit of growth; the space being filled with a clear and transparent liquid. This concentration of the vitellus toward the center of the egg is one of the first evidences of its organization; and which is further shown by the fact that in those eggs found near the orifice of the vulva, the vitellus was already divided in two segments, each of which, enclosed a central portion which was clear. (Fig. 1). While, on the contrary, those occupying the deeper parts of the uterus, were as yet an undivided mass, with a single clear portion in the center. From this and many other observations in reference to the development of the eggs of similar worms, it is quite evident that they, as well as the Strongylus, do not, in the genital tube of the female, attain a degree of organization more advanced than that just stated. Placing some of the eggs, as soon as taken from the body of the female, (24th of Nov., 1868), in moist sand, and others in a decanter of pure water, no progress was made in the division of the vitellus during the whole winter. It was only in the middle of April, 1869, four months and a half after their extraction from the female, that the divisions of the vitellus had attained four, six, or a much greater number of segments in the different ova; several even having the appearance of being quite mature. About a month later, (19th of May), in most of them, an embryo was observed which was entirely cellular in appearance, and yet executed spontaneous movements that were quite appreciable. At the end of May nearly all of the eggs contained an embryo that was fully formed. (Fig. 2). 2 Disengaging the embryo from its shell, it generally remained immovable, or executed only slow and rare movements; and, after some minutes, it visibly altered in its appearance, showing vacant spaces in its interior, and expired. This was the case in pure water, which proved that this was not the natural element for the Strongylus at its birth. Salt water preserved the same intact for a longer time; but, above all, in albumen, the embryo manifested the greatest vivacity and rapidity of movement. Adding a few drops of a weak alkaline solution and maintaining the embryo at a temperature of 30 to 35° centigrade, (86 to 95 Fahrenheit), its movements became more energetic than ever. The embryo is about one-one hundredth of an inch in length cular; diminishing insensibly in its posterior portion, and terminating in a conical tail. The head less tapering than the caudal extremity, terminates in a mouth which is a small round opening that presents a trace of six papillæ upon its border. The mouth appeared to be furnished with a small perforating tooth that could be protruded or retracted at the will of the animal. The œsophagus occupied about one-fifth of the length of the worm; and toward its anterior part appeared to be provided with three obtuse elevations, or teeth, that seem to be formed by a thickening of its internal lining. Heat has much to do with the evolution of the embroyo and with its movements. Thirty degrees centigrade (86 Fahrenheit), serving to mature the ova in a few days, while it would take weeks and perhaps months, to develop them at a much lower temperature. Many of the entozoa such as the ascaris lumbricoides, the tricocephalus dispar, etc., do not suffer from dessication; while, on the contrary, the egg of the Strongylus very soon becomes disorganized by dryness and exposure to air. This corresponds to the apparent design of its structure; its shell being pierced by a multitude of canals, it seems to be fitted to occupy places where moisture is abundant. This conformation of the ovum of the Strongylus may account for the infrequency of the animal, as compared with the great number of eggs that are produced.* Some of the eggs that have been in pure water or moist sand for fifteen months, and in which the embryo has been formed some eight months, have not in all that time erupted from the shell. And, as it has been seen that the young Strongle soon perishes in water, we are led to conclude that it is obliged to enter upon the life of a parasite even while enclosed in its shell. May this not be either directly to an animal where its development becomes complete; or after a longer or shorter sojourn in the organism of an animal of a different kind, which affords it a *It is evident from the history of this species as well as of other helminthæ that there is a harmony between the conditions which affect the development of their eggs and the place inhabited by the animal that nourishes them. |