posterior surface of the instrument, with two objective lenses.

Through the small openings in the cover, above and below the central perforation, the number of the auxiliary lenses is read. The posterior plate can be removed whenever it is necessary to cleanse the glasses, which may be about once a month.

To use the instrument conveniently, I have arranged a table which shows the most suitable combinations, representing, in near approximation, the numbers of spectacles contained in our ordinary trial-cases. Furthermore, I have calculated the shortening and elongation of the optical axis corresponding to each convex and concave glass. A third table refers to aphakial eyes, i.c., eyes in which the crystalline lens is absent. These tables will be sold with the instrument, and may be hung up in the ophthalmoscope room for reference whenever we want to determine the location of any object in the background of the eye. The measurement of the height of an elevation or the depth of a depression requires no more than the ophthalmoscopic determination of the location of the two remotest points of the morbid parts, and the addition or subtraction of their corresponding values as found in

the table.

Since I exhibited this instrument at Newport, Dr. Loring has devised a very elegant modification of his previous instrument. He has inserted into one disk ali the numbers that were formerly contained in the three disks. The disk of his new instrument has two rows of glasses, each of which, by shifting the disk up and down, can be conveniently placed behind the aperture

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ordered the instrument, but have not yet received it. If the drawing represents it in its natural size, the hole in the mirror has a diameter of 1.5 mm. only, and each of the lenses has a diameter of 2.5 mm. These dimensions are surprisingly small. To test the availability of this and similar instruments, I have tried to determine, by experiment, how far the size of the opening in the mirror can be reduced. I had a series of mirrors made, in which the diameter of the opening varied between 1 and 5 millimetres. The results of these experiments, thus far, have been as follows: The greatest brilliancy--intensity of illumination-of the ophthalmoscopic image is obtained by an opening in the mirror of 3 to 3 millimetres. If we further reduce the opening, the image becomes proportionately darker.

Openings larger than 4 millimetres in diameter render the image likewise darker, by the fact that they cast a shadow in the centre of the ophthalmoscopic field of vision.

The small openings have still another disadvantage: they act as diaphragms, cutting off the peripheral rays, and thus do not readily indicate whether the adjustment of the ophthalmoscope by means of the auxiliary lenses is accurate or not. As the correctness of the observation depends on the nicety of this adjustment, ophthalmoscopes with small apertures in the reflector are of little service for optometric purposes. They are bad instruments altogether, because they throw a great amount of light into the patient's eye, but intercept so many of the returning rays that the physician obtains a dark image. If there were no

limits in the smallness of the opening in the mirror, the problem to add the necessary number of auxiliary lenses would be simple. Thinking that an opening with a diameter of 3.75 millimetres was the most appropriate, I distributed the auxiliary lenses to two disks, and by making the edges of the disks overlap each other behind the aperture in the mirror, obtained a series of lenses as extensive as pathological or physiological research seems ever to require. The instrument, with regard to brilliancy of the image and accuracy of optometric determinations, is, it seems to me, equal to the best ophthalmoscopes; whereas with regard to completeness and cleanliness, it may, perhaps, have some advantages of its own.

Mr. President and gentlemen: I have ventured to appear before you with a specially ophthalmological subject. If I have not succeeded in engaging your interest for it. I have to accuse myself alone, for the subject would have been worthy of an abler advocate. It is certainly a triumph of medicine to possess the means of detecting, without asking the patient one question, in an anomalous refraction of the eye, the cause of his inability for work, and almost constant headache; and in detecting the cause, we have at the same time found the remedy which cures him from weakness and pain. Furthermore, it is gratifying enough to gaze through the ophthalmoscope on the varied and brilliant pictures of the interior of the eye, and to study them both for their own sake and their connection with general diseases. When, moreover, in the advancement of science, we look no longer on these changes as mere flat pictures, but measure their height and depth to a small fraction of a millimetre, on a field in which, only two decades ago, their reigned impenetrable darkness, then we have passed the lower forms of the qualitative analysis, and arrived at the quantitative. And so, as this field has been gloriously conquered, the whole vast expanse of medicine will, in the long lapse of ages, be cultivated and raised to the dignity of exact science. But since it has to be conquered step by step, I thought it might not be asking too much of a general medical society to lend at times an indulgent ear to the specialist, the small freeholder who ploughs but one acre.

Progress of Medical Science.

THE OLEATES OF MERCURY.-These new mercurial preparations, which are being used so extensively and with such success, were first introduced to the profession by Mr. John Marshall.

In a practical and extremely valuable paper on this subject, he says that the oleates are cleanly and economical, and have a much greater diffusibility or penetrating power than the old mercurial ointments, for they are absorbed by the skin with remarkable facility, and manifest the remedial effects with great promptitude. They are not to be rubbed in, like ordinary liniments, but should be merely applied with a brush, or be spread lightly over the part with one finger, otherwise they may cause unnecessary irritations. This result, however, may be obviated by the addition of a small quantity of olive oil or purified lard, according as an oleaginous or an unctuous preparation is required. In his experience, however, the addition of morphia was a great advantage, but it was necessary to use the simple alkaloid, as neither the hydrochlorate, the acetate, nor the meconate are soluble in oleic acid. For every drachm of the solution of oleate of mercury in oleic acid, one grain of morphia is to be added. As a rule, from ten to

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thirty drops are sufficient for one application. This should be repeated twice daily for four or five days, then at night only for four or five days, and afterwards every other day until a cure is obtained. Unless used in excessive quantities, the oleate does not salivate or produce any marked constitutional disorder. regard to the applicability and utility of the oleates Mr. Marshall says they seem to be specially designed for persistent or chronic inflammations, provided only that the seat of the disease be in or near to the skin. As to the preparation of this remedy, he adds: "The oleate must be prepared with the oxide precipitated by caustic potash or soda, from a solution of the metal in nitric acid recently made and well dried. The solution of mercury by oleic acid is assisted by a temperature of 300° Fahr. The 5 per cent. solution is a perfectly clear, pale yellow liquid, resembling olive oil, but thinner; the 10 per cent. solution is also fluid and perfectly clear, but as dark as linseed oil; whilst the 20 per cent. solution is an opaque, yellowish, unctuous substance, closely resembling in appearance resin ointment, melting very readily at the temperature of the body, and forming a kind of transparent, viscid, colorless varnish when applied to the skin. The chief care to be observed in the manufacture of these solutions is not to hurry the process, and not to employ a high temperature, or the mercury will be immediately reduced."

In cutaneous diseases the 5 per cent. solution, without morphia, is recommended. ` It has been found particularly serviceable in sycosis menti. In congenital syphilis a piece of the 20 per cent. ointment, about the size of a pea or a bean, may be placed in the child's axillæ night and morning for five or six days, and without any sign of uncleanliness, produces constitutional effects. As a topical remedy for certain local manifestations of syphilis, such as the non-ulcerating forms on the head, face, and neck, the 10 per cent. solution is a valuable adjunct to other treatment.

DIAGNOSIS OF EARLY PREGNANCY.—Among other valuable papers read at the recent meeting of the British Medical Association, was one by Dr. Rasch, in which he called attention to an important symptom of early pregnancy, which had never before been mentioned by the leading obstetrical authorities.

After detailing the principal symptoms which are to be found in the text-books, Dr. Rasch said that no opinion should be expressed in any case unless the uterus had been made out beyond doubt by the bimanual examination. The vaginal examination should always be made by two fingers, unless circumstances forbade it, as by so doing results much more accurate could be obtained. An enlargement found, the distinction had to be made between enlargement by hypertrophy or by tumors, and enlargement by pregnancy. To solve this difficulty, the author has continued his investigation in a very large number of cases, of which he kept notes for nearly ten years, and enlarged experience has fully borne out what had helped him in making a few times a right diagnosis where better men had failed. This important symptom was fluctuation. That it must be felt very early seemed to him, a priori, certain. The best way to feel it was to introduce two fingers into the vagina, while the other hand steadied the womb through the abdominal walls, and alternately to manipulate the uterus with the two fingers. In some part of the uterus the fluctuation would be found often in one corner of the fundus, sometimes lower down. In most cases of early pregnancy the author found the uterus anteverted, and then the manipulation was more easily done than when the womb was retroverted. At first it

was usual for fluctuation to be felt only by the fingers in the vagina, sometimes, too, by the outer hand at the same time. After three months, it would be mostly felt by outward manipulation alone, but we should never trust to that only. The catheter should always be introduced when accurate results were desired.

ANTIDOTE TO PHENIC ACID. The poisonous effects of phenic acid are due to the acid itself, and not to the alterations to which it is subject.

Mr. Husemann has proved, by numerous experiments, that the alkalies and alkaline earths are true antidotes to this acid, while the fat oils, glycerine, etc., are entirely without effect.

In cases of poisoning, it is necessary to use these antidotes in large excess and in solution, the saccharate of lime being employed successfully. This is obtained. as is known, by dissolving 16 parts of sugar in 40 of distilled water, and adding 5 parts of caustic lime. Digest for three days, stirring from time to time, filter and evaporate to dryness. The product thus obtained constitutes the saccharate of lime; it dissolves easily in water. Journ. de Pharm. et de Chim., Sept. 1873. ACTION OF FRESH CHOLERA DISCHARGES UPON ANIMALS.-An interesting series of experiments with the discharges from cholera-patients was made during the latter part of July, of this year, by Andreas Högyes, of the University at Pesth, a report of which is published in the Centralblatt für die Med. Wissensc., No. 50. The points which it was sought to determine were, in brief, the following:

I. Do fresh cholera discharges operate injuriously upon the organism of lower animals, and under what manifestations?

II. Does an artificially excited catarrh of the stomach and bowels increase the susceptibility to the action of the cholera discharges?

III. Can a current of air bear away particles from the discharges, which are capable of affecting the organism injuriously, and what difference is there in this respect between non-disinfected and disinfected cholera discharges, simple diarrhoeal discharges, and putrifying fluids?

IV. Are cholera discharges freed from their form(living) elements still able to act upon animals?

V. What portions of the disinfected or non-disinfected discharges does the air-current bear away, and what is the further destiny of these form-elements when they fall upon a neutral medium or one adapted to their development? In what manner do these clements modify the action of this medium?

To decide the first and second questions, fresh cholera discharges were given to healthy dogs and to others, in which an artificial catarrh of the stomach and intestines had been excited by the administration of croton-oil, sulphate of copper, etc. Both dogs were made sick, with frequent vomiting and diarrhoea. But while the previously healthy animals recovered in three or four days, those in which a catarrh had been excited died the day following.

To determine the third question, rabbits were placed under a bell-glass and exposed to air which had become impregnated as desired, from either cholera discharges, disinfected or not disinfected, diarrhoeal discharges, or putrefying fluids. Two rabbits, in one of which a bronchial catarrh had been produced by inhalations of ammonia, were exposed for twenty-four hours to air from cholera discharges not disinfected.

On the third day following, violent purging set in, and both animals became soon cold and collapsed. The one in which a bronchial catarrh had been excited died first, and the other five hours later. A rabbit

exposed for twenty-four hours to air from disinfected cholera discharges remained well. Another, exposed for an equal length of time to atmosphere impregnated from simple diarrhoea-stools, escaped uninjured, while another, which remained for twenty-four hours in atmosphere contaminated from putrid fluids, though at at first made insensible, afterwards recovered without As to the fourth point, cholera discharges were injected into the jugular veins of dogs and guineapigs, the discharges in one case having first been freed from their form-clements by thorough filtration, and in the other not. The effect in both instances was the same.

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made to pass through fresh cholera discharges, both To determine the final points, a current of air was disinfected with carbolic acid and not disinfected, and then conducted through two separate vessels, which contained, respectively, an indifferent fluid-medium, and one adapted to the support and development of any living forms which the current should bring to it. The two fluids used were distilled water and the fluid of Cohn. In a short time, in the fluids communicating with the undisinfected discharges, a considerable number of form-elements had accumulated, which proved to be, almost exclusively, the bacteria which are usually found in putrid animal fluids. In twelve hours Cohn's fluid had become clouded and milky; in twenty-four hours it was covered with a thick bluish-green fungous slime, and emitted a foul odor. The distilled water remained clear. Both these fluids, when injected into the veins of dogs and rabbits, caused the same symptoms as after injection of the cholera discharges themselves. This was also true of the fluid of Cohn, after its fungous elements had been quite removed by filtration, showing that these elements are, at least, not the only source of infection. Similar experiments with discharges which had been disinfected with carbolic acid, showed that the organisms which the air-current brought to Cohn's fluid were incapable of propagation. Upon injection of the distilled water and fluid of Cohn, after previous disinfection of the discharges by carbolic acid, only symptoms of carbolic-acid poisoning were manifested.

PROFESSOR ZEISSL ON THE TREATMENT OF SYPHILIS.-After some experimental treatment of syphilis in its various manifestations, Zeissl expresses the following conclusions:

"The preparations of iodine judiciously administered, with the appropriate regimen, are able to cause the disappearance of the first manifestations of syphilis, or, at least, to so modify the disease that it yields to a small number of mercurial inunctions, without a subsequent recurrence of relapses, that is, so that the syphilis may be regarded as definitively cured." He further observed that the initial appearances succumbed sooner to an early mercurial course than to the iodine treatment. While the later phenomena quickly disappeared under iodine, the initial indurations resisted longer. The affections of the mucous membranes, as papules upon the tongue, and in the whole region of the mouth and pharynx, yielded much earlier to the treatment with iodine, at the most necessitating occasionally a slight cauterization, while with mercurial treatment they persist for a longer time. Instead of the iodide of potassium, the following formula was employed, on account of its greater cheapness: