11 cases were admitted, and the cases in private practice were rapidly increasing in number. By the 22d, forty-five deaths had occurred in the city, and after this the epidemic rapidly extended. It was stated that the first three victims were cooks, who went every morning to the principal market, within a cable's length of the vessel; but this was erroneous, as the Swanton was nearly a mile away, and these cases occurred on the 15th, after several other cases had been noted. The disease reached its zenith about the 28th, and declined steadily from the 1st of January.

After the disease appeared, almost every vessel that left the city soon had cases aboard; persons having the disease and dying of it, were carried to all the landings, towns, and cities up the Mississippi, as high as Cincinnati. In many of these places it spread to a limited extent; in others it did not; in no place did it prevail as an epidemic. It spread among the plantations along the river and in the interior of Louisiana. To some of these the infection appeared to be directly carried; at others it began without any communication with an infected district. It prevailed at Houston, Texas, while Galveston on the sea-board escaped, although on the line of travel from New Orleans to Houston. At the Charity Hospital, as many as 50 cases occurred among the nurses, servants, and patients.

Some other facts are well worthy of attention. The Guttenburg left Hamburgh in October, and six or seven deaths occurred before she got out of the Elbe. When she got to sea the disease disappeared, and did not again return. So that in this case, getting to sea out of the infected district arrested the disease.

The analogy between the cases of the New York and the Swanton is certainly remarkable: both vessels left a port in which no cholera case was known, with emigrants; the time of departure was nearly the same, viz. the Swanton on the 2d or 3d of November, the New York on the 9th; both were bound to different ports of the same country, and therefore probably followed nearly the same track; in the Swanton, which sailed on November 2, cholera appeared after twenty-six days, therefore on or about the 28th of November; in the New York it appeared on the 25th of November. In these cases it appears possible that both vessels may have been nearly in the same position, when they were attacked by cholera. Considering, then, all the circumstances of the case, the departure of those ships from a healthy port, the length of time they remained free from sickness, their possible vicinity to each other when they were attacked, the fact of their being emigrant ships, and therefore presumably badly cleaned and ventilated, it does not appear improbable that both ships became nearly at the same time subjected to some peculiar influence, which caused in both cases an analogous and independent manifestation of the cholera poison.

Dr. Fenner, the reporter of the New Orleans epidemic, says, "Whether it be a mere coincidence that epidemic cholera broke out in this city, just at the time when a vessel arrived, having some cases of cholera on board, or that said vessel brought the infection, which rapidly spread through the whole community, is an exceedingly debatable question." And at the end of his Report he remarks, that the few facts he has brought forward do not decide about the contagiousness or transportability of cholera. It would seem, therefore, that the channel of introduction, or the reality of actual importation of cholera, into New Orleans, may yet be a matter of dispute.

PART FOURTH.

Periscope.

ANATOMY, PHYSIOLOGY, AND ORGANIC CHEMISTRY.

On the Intimate Structure and History of the Articular Cartilages.
By Dr. JOSEPH Leidy.

THIS paper contains a minute description of the arrangement and mode of multiplication of the cartilage-cells; the groups of which are stated to lie perpendicularly in the deeper part of the cartilage (that nearest the attached surface), and obliquely or irregularly as they approach the free surface, whilst at and near that surface they lie parallel to it. The deeper groups are composed of a larger number of cells than the superficial; and in the stratum forming the free surface, single isolated cells are not unfrequent. The free surface is covered in the foetal state by a synovial membrane; of which the two characteristic elements-basement-membrane and epithelial cells may be clearly recognised. But after birth, it appears to be gradually destroyed by pressure and attrition, and by the retirement of the superficial vessels towards the circumference; and appears in the adult to terminate at the margin of the cartilage, a very little in advance of the circulus articuli vas culosus. The phenomena of the multiplication of the cartilage-cells by division are described as closely resembling those of cell-multiplication in the simpler Algæ; and favour the idea that the cell has a protoplasmatic envelope, or primordial utricle, within the regular cell-wall, from which it seems to retire when the constriction that leads to the duplication first shows itself. The division of the nucleus does not seem to be essentially connected with that of the cell itself.-The matrix of the cartilage-cells is asserted by Dr. Leidy to have a distinctly filamentous arrangement, each filament consisting of a row of very fine granules. These are best brought into view by tearing a very thin shred from the fractured edge of an articular cartilage. The filaments, like the cell-groups, are arranged perpendicularly to the attached surface and parallel to the free surface, where they form a sort of membranous layer that holds together fractured portions of cartilage.—Amer. Journ. of Med. Sciences, April 1849.

On the Development of the Purkinjean Corpuscles in Bone. By Dr. JOSEPH LEIDY. DR. LEIDY'S observations confirm the idea of Schwann, that the bone-corpuscle, or lacuna, is truly a cell, of which the canaliculi are radiating prolongations, analogous to those of the pigment-cells; and he further thinks that this cell is one of the residual cartilage-cells. The following is his account of the process of ossification, as observed in the frontal bone of a human embryo of two inches in length. "After the primitive ossific rete has been formed from the deposit of the osseous salts, inclosing groups of cartilage-cells in the areola, the further deposit takes place in a fibrous or line-like course from the parietes of the areola of the primitive osseous rete, to the interspaces of the cartilage-cells nearest to, or in contact with, the sides of the areola. At this period, the cells shoot out or extend their canaliculi between the fibrillæ just formed, and then the cell-wall and continuous walls of the canaliculi fuse with the translucent, homogeneous, or hyaline substance of the cartilage existing between the cells and the osseous fibrilla, and with the fibrilla

themselves, by the deposit of the osseous salts. The period of the formation of the canaliculi appears to be quite definite, occurring during the deposit of the osseous salts, and not before; to such an extent is this the case, that I noticed in several instances, cells which had formed their canaliculi upon the side which was ossified, while upon the other side I could not distinguish any trace of them.-Proceedings of Academy of Natural Sciences, Philadelphia, Nov. 1848.

On Hæmatozoa in the Rat. By M. CHAUSSAT.

THE occurrence of worms in the blood has hitherto been accounted a rare phenomenon; but M. Chaussat states that he has found filaria in the blood of all adult black rats which he has examined. He has not found them in the blood of young rats. He has recognised the eggs in the liver; where M. Lebert has observed them in the rabbit also.-Gazette Médicale, No. 13.

On the Arrangement of the Muscular Fibres in the Vena Cava Inferior of the Horse. By M. CLAUDE Bernard.

Ir is asserted by this able experimenter that prussiate of potass, introduced into the stomach and absorbed by the radicles of the vena portæ, is not conveyed to the heart, but is directed towards the kidney by a sort of reflux in the inferior vena cava ; and he finds this experimental result corroborated by the peculiar structure of that vessel in the horse. From the hepatic to the renal veins, there extends a ring of muscular fibres (non-striated), very apparent to the naked eye, composed of longitudinal fasciculi, which terminate abruptly above the entrance of the hepatic vein, and below that of the renal. Such a structure appears well adapted to produce the supposed reflux.-Gazette Médicale, No. 17.

On the Direction assumed by Plants. By PROFESSOR MACAIRE, of Geneva. THE author first examines experimentally into the causes of the Curling up of Tendrils; which Knight endeavoured to explain by the unequal action of the light on both sides of the tendril, and which was attributed by Decandolle to the obstacle afforded to vegetation by the contact of the leaf-stalk with the body adhered to, on the side where it touches it. Of the plant on which he experimented, though a common weed in the gardens of Switzerland, he is unable to give the name with certainty; it was probably the Smilax aspera. He found that when the tendril is touched by any solid body whatever, on a point of the surface not too far from the extremity, it immediately contracts on one side, so as to form a curve over the surface of the body and to embrace it closely, until seven or eight coils have been formed around it; and this is done so rapidly that three turns of the helix are sometimes made in a quarter of an hour. The nature of the body presented has no influence on the process; the tendrils coiling as readily over one substance as another, so that they will cling to other portions of the plant from which they spring, though obviously destined to obtain support for it from others. As these and other phenomena cannot be accounted for by any action so slow as the ordinary processes of nutrition, it appears necessary to admit the existence of irritability as a vital property inherent in the tissues of the tendril; this property is found to cease when the tendril is separated from the parent plant; and, like the irritability of sensitive plants, it is excited, modified, or even suspended or destroyed, by the influence of vegetable or mineral poisons.

The next subject examined is the Inclination of Stems towards the Light; which was attributed by Decandolle to the more rapid and more complete solidification of the tissue, by exhalation and fixation of carbon, on the side of the stem exposed to light. Professor Macaire first inquires if such a special attraction is exercised by light on the green parts of a plant, as to cause the entire plant to move towards light if permitted to do so; and his experiments on plants of duckweed, and on

germinating plants of various kinds attached to floats of cork, lead him to a negative conclusion. He found that, however long it might be necessary for a stem to grow, in order to reach the light, its base, attached to the cork float, always remained in the same spot. In one instance, a germinate seed of mustard having been placed on a float in a tumbler surrounded by dark paper, but near an aperture admitting luminous rays, the plant put forth a stem which passed all round the tumbler, to spread its leaves in that part of the vessel in which the luminous aperture was; once there, the stem did not extend itself beyond it, but grew erect, although the light was not strong enough to render it entirely green. Thus, although a very slight motion of the float would have brought the entire plant within range of the light, its position remained altogether unchanged, whilst the stem went, as it were, in search of it. The observations of Professor Macaire are opposed to the hypotheses of Decandolle in this case, as in the preceding; since he found that the stems grew straight towards the light, without the incurvation or bending which that hypothesis assumes. Where young plants already vigorous were placed on the floats, in the dark portion of the vessel, their green stems took on little or no ulterior development; but from the neck of the root there grew out another stem, white and etiolated, which spread itself along the water to reach the diaphragm and the light portion of the vessel, where it grew erect and put forth its leaves.

The next subject examined is the Direction of Leaves; that is, the tendency of those which have two surfaces of different hues to expose the deeper coloured to the sky, and the paler to the earth. Professor Macaire's experiments lead him to the same conclusion with that of other physiologists, that light is the only agent in the turning over of leaves, and that it does not act by a physical attraction properly so called, but by its influence upon the individual parts of the tissues on which it falls. This influence is the more rapid and energetic, all other circumstances being alike, the greater the difference between the two surfaces of the leaves experimented on. It was maintained by Bonnet and Dutrochet that the turning over of leaves always takes place by a flexion or torsion of the foot-stalk; but Professor Macaire has demonstrated that the flat portion of the leaf, or even a separate portion of it, can turn itself over. Thus when an entire branch of geranium was immersed in water in such a way as to expose the under surface only of its leaves to the light, all the young leaves turned themselves over in three days by moving on the point of insertion of the flat part of the leaf into the foot-stalk; and in other experiments in which the light was kept from falling by means of a screen on the upper surface of leaves, and was directed by means of a mirror towards the lower, the margins of the leaves bent down in such a manner as to bring their upper surface within the influence of the mirror. Upon repeating such experiments with glasses of different colours, it was found that the leaves turned themselves over most readily in blue rays, and next in violet; but that they remained motionless in red.

Professor Macaire then inquires experimentally how far these results are attributable to the influence of light on the nutritive functions in which the leaves are concerned, and comes to the conclusion that their explanation is to be sought here. He found that the exhalation of fluid from the leaves is always greatly augmented by the exposure of their under surfaces to light, the increase being double, triple, or even more. It is obvious that this is one principal cause of the unhealthiness of leaves which results from the inverted position being forced upon them. Another cause is to be found in the diminution of the rate of decomposition of carbonic acid, which takes place under the same circumstances, and to about the same extent. According to Professor Macaire, the exhalation is greater under blue glass than it is in diffused light, and the difference between the amount of exhalation from the upper and under surfaces of the leaves respectively is most strongly marked; on the other hand, the amount of exhalation under red glass is reduced to about a sixth, and the difference between the quantity exhaled from the two surfaces of the leaves is proportionably lessened.-Philosophical Transactions, 1848.

Microscopical Examination of the Contents of the Hepatic Ducts, with Conclusions founded thereon. By T. WHARTON Jones, F.R.S.

IN the contents of the larger hepatic ducts there are seen, on microscopical examination,-1st, the detached columnar epithelium-cells of the ducts themselves; 2d, free oval nuclei, which appear to have been derived from cells of this kind; 3d, free round nuclei, apparently derived from the proper hepatic cells; 4th, minute granules, free or in amorphous flakes, globules of oil, and fragments of cell-walls. In addition to these, in the smaller ducts are found cells resembling those of the parenchyma of the liver, except in being usually paler, on account of the contained granules and globules being fewer and more minute.-Having, by way of comparison, examined the contents of the pancreatic duct, and recognised in it, with its own columnar epithelium, the free nuclei and granular amorphous matter resulting from the disintegration of the secreting cells developed within the vesicles of that gland, the author considers that, from the analogy of the products of the secreting action in the two cases, an argument may be fairly drawn in favour of the analogy in essential nature between the cells of the hepatic parenchyma and the endogenous cells of the pancreas and other glands of ordinary construction, This deduction helps to confirm the view of the structure of the liver propounded by Dr. Leidy, of which an account was given by us not long since.-Phil. Trans., 1848.

On the Artificial Production of Diabetes. By M. CLAUDE BERNARD. IT is asserted by M. Claude Bernard that, by passing a sharp instrument into the fourth ventricle, the urine is speedily caused to present a saccharine impregnation, its other constituents remaining unchanged. His first experiments were made upon rabbits; but he has since performed the operation upon a dog, in whose urine a notable quantity of sugar was found at the expiration of twenty minutes, although none existed there previously.-Gazette Médicale, 2 Juin, 1849.

On the Composition of the Salts of the Blood, and of their Relations to the Formation of Vesical Calculi. By M. VERDEIT.

THE author states that the proportions of the different saline compounds in the blood are greatly affected by the nature of the diet; the blood of animals nourished exclusively on flesh being rich in phosphates, with alkaline bases, and containing scarcely any alkaline carbonates; whilst the blood of animals restricted to vegetable diet presents the reverse condition, the alkaline carbonates being present in large amount, and the phosphates existing in it in very small quantity. These differences present themselves not only between the blood-salts of carnivorous and of herbivorous animals respectively, but also between those of the same animal nourished for a time upon an animal and a vegetable diet exclusively. Thus the blood of a dog fed upon meat for eighteen days yielded 12.75 parts of alkaline phosphates in 100 of ash; but when it had been partly fed for fifteen days upon bread and potatoes, the proportion fell to 9 per cent.; "and if," says the author, “I had been able to sustain it on an exclusively vegetable diet, the amount would have fallen to 2 or 3 per cent., as in the blood of the ox or the sheep." These observations, if confirmed, will have a very important bearing upon the treatment of calculous disorders, since urinary deposits consist, in by far the greater number of cases, either of uric acid or of phosphates. Now, uric acid is sparingly soluble in water, and still less so in acid urine [this does not agree with the statements of Liebig, which have been confirmed on this point by others]; but it is rendered much more soluble by the presence of alkalies in the urine. Now, as the acidity of the urine is due to the excess of phosphoric acid, which is the result of an animal diet, a vegetable diet, which will render the urine alkaline like that of the herbivorous animals, is indicated. On the other hand, if the phosphates constitute the materials of the deposit, their amount in the blood and urine may be lowered in the same manner.-Gazette Médicale, 2 Juin, 1849.