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.

It 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 apperrs well adapted to produce the supposed reflux.-Gazette Médicale, No. 17.

On the Directions 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 certainly; 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 clssely, 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 remain. ed 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 qauntity 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.

Ir 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. VERDIET.

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 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 mateials of the deposit, their amount in the blood and urine may be lowered in the same manner.- -Gazette Médicale, 2 Juin, 1849.

PATHOLOGY AND PRACTICE OF MEDICINE.

On Crises and Critical Days. By M. BRICHETEAU.

M. BRICHETEAU testifies in the present paper to the great benefit he has frequently derived during a long practice from the observation of crises as inculcated by Hippocrates. "Several times has it occurred to me to suppress a prescription too hastily written, on learning that an abundant sweat or deposit in the urine has occurred in the night. If asked why the doctrine of crises is now of so little account, we may reply with Van Swieten, that physicians in full employment, who alone have the opportunity of observing them frequently, are so occupied by the great number of patients they have to visit, as to be unable to keep an exact account of the symptoms and progress of disease; and the patients themselves often force themselves into an erroneous course, and oblige them to deviate from the track pointed out by the masters of our art by their impatience to get well and their astonishing propensity to swallow medicines. The sad truth, indeed, must be told, that it is far easier for a practitioner to bleed or purge his patient after a rapid examination of the tongue and pulse, and to prescribe a variety of internal and external remedies from the indications of certain symptoms, than it is to observe day by day the successive phenomena of disease, discuss their value, and withhold the hand in presence of critical changes, in spite of the observations of the invalid or his friends! To a certain point the very progress of the medical art itself has been inimical to the reception of the doctrine of crises. Our improved means of diagnosis renders the study of general symptoms, the conditions of the various apparatuses secondarily affected, and the indications which these may furnish of the resolution of disease, less necessary than heretofore. . . . . To exhibit the importance of the observation of these crises, it suffices to mention the advantages derivable from sparing the patient the useless administration of medicines, the application of painful revulsives, or the employment of drugs capable of deteriorating their organs, enfeebling their power and retarding their convalescence. Who is there unaware of the incendiary ravages of medicines when given without discernment? The most penetrating mind fails to seize the natural course of the disease amidst the accidents produced by a perturbatory medication."

According to Galen, a crisis is a change which occurs in the course of a disease, whether for good or evil, conducive to cure or death. It is in fact a change. It is generally favorable, announced by precursory phenomena, and characterized by abundant excretions, hemorrhages, &c. Although showing itself generally as a consequence of the administration of medicine, this is not its origin, as it may present itself when no medicine whatever has been given; and most of the ancients attributed the phenomenon to the spontaneous action of the vis medicatrix, effecting an advantageous modification in the economy. If the change be only a result of the re-establishment of excretions suspended at the commencement of the disease, of the re-establishment of a general equilibrium, or of a return to the normal condition, and if in place of being, as the ancients supposed, an active cause, it is only a result, it matters little, since it is still an essential and integrant part of the disease, which, if the account of a case is to be rendered complete, is always to be noted when it presents itself. It has been pretended that, in order that a crisis may be entire and complete, a rigorous expectancy, dangerous to the life of the patient, is essential; but this is an erroneous view of the subject, since Hippocrates and Galen employed various internal and external medicinal agents to aid nature when too enfeebled, and to develope imperfect crises.

The days on which crises are determined, are called critical, and the others non-critical. The regarding as critical too great a number of days, has greatly exaggerated the difficulty of applying the doctrine of crises to the bedside of the patient. The principal critical days were considered to be the 7th, 14th, and 20th. Others, as the 9th, 11th, and 17th, were of a secondary rank, while the 3d, 4th, 7-17. 24*

and 5th occupied a still inferior position; and the 6th had so bad a reputation as to be termed the tyrant. At the 8th and 10th were sometimes produced abortive crises, while none were exhibited on the 12th, 16th, and 18th. The 7th day has always been considered the critical one par excellence. The days of inferior critical power were said to be indicators or precusors, announcing by an amelioration or precursory phenomenon a perfect crisis of the three radical days. Thus the 4th is the indicator of the 7th, or, in the words of Hippocrates, those whose ailments will determine on the 7th day have an abundant urinary deposit on the 4th. The 11th is the indicator of the 14, and the 17th of the 25th. These indicating days sometimes themselves furnish crises, and become exceptionally radical. M. Brichteau gives the abstracts of many cases in which, by attentive observation of these various days, he has been led to their more satisfactory treatment."-Rev. Med.Chir., t. iv, pp. 259-67.

On Eruptive Fevers without Eruption. By M. TROUSSEAU.

SOME practitioners doubt the accuracy of the facts related by some of the great observers of former times, concerning the existence of eruptive fevers without eruption. They have been especially considered as apocryphal in our times, when the localization of disease plays so large a part in the no:ological systems. But when we consider that all pathologists admit that these diseases attack the mucous membranes as well as the skin, it is obviously improper to consider them as diseases of the skin; and in many cases we observe the eruption to be so very slight, that we can very well imagine it may in others be absent, without the necessity of denying the existence of the disease.

In illustration of such occurrence, Dr. Trousseau details the history of a Lilliputian epidemic that occurred in a retired hamlet near Paris. The hamlet only contained three families, of twelve inhabitants, none of whom had had scarlatina. It appeared in a mild form; every one of them was ill, but in different degrees and forms. Eight persons had the rash and angina in their most distinct forms, but four only suffered from severe fever, with angina and desquamation of the tongue. In these the convalescence was tedious, especially in one case wherein anasarca followed. Who can doubt that these four were likewise subject to scarlatina, although, had they been presented to the observer in an isolated manner, he being unacquainted with their antecedents, the nature of the case would have been overlooked.

Two facts which have recently occurred in the hospital alike serve to show the possibility of the occurrence of eruptive fevers without eruption, and the difficulty of judging correctly concerning such cases when seen in an isolated condition. A boy, æt. 7 was brought in suffering from croupal cough, laborious respiration, and high fever; an emetic and some small doses of calomel were given, and next day the character of the cough was much better, but there was still much fever and oppression, and ausculation indicated a capillary bronchitis. As the eyes were observed to be somewhat injected and weeping, the tongue red at the tip, and a little blood plugged the nostrils, it was deemed probable that it was a case of measles, but it was only by very diligent search some rose-coloured non-prominent spots could be detected on the forearms. On compressing the arm, so as to inject these more, their measly character became evident. In a few hours they entirely disappeared, never more to return,“ though the entire body of the child was whipped with nettles twice in one day (!)." It is evident that the diagnosis of this disease could not have been made had not the arms been examined just when they were, and that even this small manifestation would not have taken place had the arms been exposed to the cold, instead of enveloped in a warm dress. About the same time a child, æt. 2, was brought in, suffering from a severe form of pleuropneumonia, having been ill for eight days. The next day an eruption of measles spread all over the body. No physician, let his sagacity be what it might, could have recognized the measles the first day, and yet it is evident that in this child, as