15 c. c. point there is another mark, facilitating the addition of reagents to cause precipitation.

BAUSCH & LOMBOPTCO. ROCHESTER, NY.

With this instrument a speed of 3000 revolutions a minute can easily be maintained and a much greater speed can be reached if desired. Tubes for the examination of milk, sputum and water accompany the instrument.

The Centrifuge and Urine Analysis. In no one way is the centrifuge so useful as in urinary analysis. The examination of the urinary sediment is all important from a diagnostic standpoint, as it is in it that casts, blood corpuscles, pus cells, epithelial cells, bacteria and other pathological products are to be found. Where the centrifuge is not used, it is necessary in order to get a fair sample of the sediment to set the urine aside in a conical glass for from twelve to sixteen hours, in order to allow it to precipitate. During that time, and especially in warm weather, bacteria develop in the urine very rapidly, and chemical changes take place, which often cause the total disin. tegration of any morphological elements present, such as casts, blood corpuscles, etc. Such a sediment when examined would give an entirely erroneous diagnostic result, a result which might cause untold injury to those interested. With the centrifuge, however, this source of error is entirely obviated, for within five minutes after the fresh sample of urine is received, the sediment may be precipitated and placed under the microscope for examination. The

diagnosis made from such a sediment may be depended upon.

Method of Procedure.-In order to precipitate the anatomical elements which may be present in the urine,. as casts, blood corpuscles, etc., the tubes should be filled to within 3/4 in. of the top with urine, and the handle of the instrument rotated at a speed of about sixty turns a minute for three minutes, at the end of which time it will be found that the distal extremities of the tubes contain a precipitate which consists of the solid constituents of the urine. A large portion of the urine is now poured carefully off, and a portion of the sediment placed upon a slide and covered with a cover glass for examination under the microscope. The chances of finding casts by this method are infinitely greater than by the old method.

In this precipitate will also be found any chemical elements which may be present, as such, in the urine, as uric acid, urates, calcium oxalate,

etc.

Chemical Examination by Centrifuge-The most important chemical elements, from a diagnostic standpoint, present in the urine are the phosphates, sulphates, chlorides, and indican.

Determination of Phosphates.-The graduated tube of the centrifuge is filled to the 10 c. c. mark with fresh urine, and 5 c. c. of the following solution is added:

Magnesium chloride,

Magnesium sulphate, aa part j. Aq. distillata, parts viij. Liquor ammonia, part j. The centrifuge is then rotated at a speed of sixty turns of the handle per minute for three minutes, when all the phosphates are precipitated. The normal amount of phosphates as shown by this test is 8 to 12 per cent.

Determination of Sulphates.-The graduated tube is filled to the 10 c. c. mark with fresh urine, and 5 c. c. of the following solution is added: Baric chloride, parts iv. Hydrochloric acid, part j. Distilled aq., parts xvj.

The handle is rotated at a speed of sixty turns per minute for three minutes, when the sulphates are precipitated. The normal amount is about I per cent.

ne with water and tested as at it the result multiplied by two. this resume of the diagnostic the centrifuge it will be seen able a help it is in clinical it is not too much to say rect work it is indispen.

ATOLOGICAL

MEDY.

CANTRELL, M. D., LPHIA, PA.

e Skin in the Philadelphia College for Graduates in Medicine, .matologist to the Philadelphia Hospital and to the Frederich Douglass Memorial Hospital.

THE

HE USEFULNESS of the mercurials in the practice of dermatology is undoubted, but the choice must be made from the several different salts so as to comply with the demands of the affection under treatment. The emplastrum and ointment of mercury, the yellow oxide and its ointment, the red oxide. and its ointment, the mercurous chloride and the oleate as well as the ointment of the nitrate all have select duties to perform upon the external skin. They may be chosen for treat ment of conditions affecting the eyelids or their duty may consist in relieving some more aggravating affection occupying a large tract of epidermis, they may be used to prevent contamination through the germs of the air or to assist in removing parasites that may affect the skin or manifold uses may be mentioned in which one or the other have performed cures. Internally the mercurial pill, the mercurous chloride and both the red and green iodide have innumerable uses in the treatment of disease. The poisonous qualities of some of these limit their usefulness on account of the fear entertained that some careless person may unwisely lay it around or that its application may cause fear in the minds of those who may be aware that they are using a poison. This fact contributes some theory why the mercuric chlo ride is not of so decided advantage in the treatment of cutaneous eruptions but if carefully advised and carefully placed in the hands of some responsible person this fear is greatly diminished. It is positively injudici

believe much is necessary to be told because it has been so much used in this capacity and has performed such manifold cures and assisted or prevented the growth of germs in the effected areas that it has established its usefulness in this direction.

In using the mercuric chloride in dermatology, it may be advised either in pill, ointment or in liquid form. The dose and quantities will be mentioned when speaking of the several affections in which it may be advised.

Externally it will be found advantageous to a greater or less extent and while it may prove useful in some cases of the affections to be mentioned it will likewise fail to produce a cure..

Pediculosis.-The ravages of the pediculus may be checked by the application of this remedy. In treating a case of this condition occupying the hairy parts, it will be wise to make use of a liquid preparation, in the strength of from one to four grains of the salt to the ounce of solution, the weaker the strength. the more preferable for the first ap plication, but in those cases affecting the non-hairy regions it will be better to use an ointment so as to keep in close contact with the skin at all times, the strength should vary from one-half to about two grains to the ounce of ointment. I have found it unwise to use the mercurial ointments on the hairy parts because the parasite passes over it without touching it.

Tricophytosis.-The vegetable parasites of the skin are removed or killed by the mercuric chloride. Tinea circinata may easily be cured. by its use. The strength of ointment may vary from one-half to two grains to the ounce of ointment, using either lanolin, petrolatum or ointment of zinc oxide, according to preference. This application should give a cure in a very few days if it is applied by

strating other bacteria, as pneumococci, streptococci, etc., which may be contained in sputum, and also in demonstrating Charcot-Leyden crystals and the spirals of Curschman in the sputum from asthmatic patients. The Centrifuge and Water Examination. In the examination of water the centrifuge is very useful, for with it all solid particles in suspension are quickly precipitated. In this way any micro-organisms present may at once be demonstrated, as also low forms of vegetable life and any foreign matter. In order to demonstrate the presence of bacteria it is only necessary to fill both tubes equally with water and rotate as rapidly as possible for three or four minutes; the upper portion of the water is now poured off and cover slips prepared from the sediment, and stained with any of the aniline colors, preferably fuchsin or methyl blue.

For the collection of diatoms and the lower forms of animal and vegetable life, the centrifuge will prove invaluable to the student of natural history, as many forms can be secured which would either be destroyed before precipitation could naturally occur, or would be missed in the examination as commonly made. The author believes that with the aid of this machine a method both quicker and surer than those now in use will be evolved for the determination of the value of any given water for drinking purposes.

The Centrifuge and Milk Examination. One of the most important questions now before the medical world is the rôle played by milk in causing tuberculosis. It is a well known fact that milk from tuber. culous cows often contains the tubercle bacillus, even though the udder may not be diseased. Such milk, it is needless to say, is most dangerous to the public health, and hence the importance of determining whether milk from a suspected source contains the tubercle bacillus or not. A search by the old method for tubercle bacilli in milk is a most arduous one and one that is not generally crowned with success, as only a very small quantity of the milk can be examined by the ordinary cover glass method. If, however, the centrifuge be used, we can say as in sputum examinations,

"the probabilities of finding them (the tubercle bacilli) are increased as many times as the volume of milk contained in the tubes is greater than the volume of milk smeared upon the cover glass with the old method."

In making an examination of milk for tubercle bacilli, both tubes of the centrifuge should be equally filled and rotated at as great a speed as possible for three minutes. Cover glass preparations should then be made of the sediment and stained as for sputum. This method will reveal the bacillus in milk where they are so few in number that the ordinary method could not detect them. Other bacteria, which are present, may of course be demonstrated in the same way, omitting the decolorizing with nitric acid.

Estimation of Fats.-The amount of fats in any given sample of milk may be estimated with the special milk tubes, which are here illustrated.

As the fats are the lightest portion of the milk they are to be found in the proximal portion of the tubes after rotation, so that a special graduated tube is necessary.

Leffman and Beam's method for the determination of fats in milk is at once accurate and easily carried out. The milk tubes are filled to the 5 c. c. mark with the milk to be tested, then I c. c. of the following solution is added and mixed by shaking. The solution.

Hydrochloric acid, parts 50. Methyl alcohol, parts 13. Fusel oil, parts 37. After thoroughly shaking sulphuric acid of Sp. Gr. 1.83 is added drop by drop, while the milk is constantly shaken, until the tubes are filled to the zero mark. They are then rotated at a speed of sixty turns of the handle per minute for two minutes, and the per cent. of fats read direct from the scale. Good cow's milk contains about 3.50 to 4.00 per cent. of fat.

If the fats read over 5 per cent., the milk should be diluted its own

volume with water and tested as at first, but the result multiplied by two. From this resume of the diagnostic value of the centrifuge it will be seen how valuable a help it is in clinical work, and it is not too much to say that for correct work it is indispen sable.

MERCURIC CHLORIDE AS A DERMATOLOGICAL REMEDY.

BY J. ABBOTT CANTRELL, M. D.,

PHILADELPHIA, PA.

Professor of Diseases of the Skin in the Philadelphia Polyclinic and College for Graduates in Medicine, Dermatologist to the Philadelphia Hospital and to the Frederich Douglass Memorial Hospital.

THE

HE USEFULNESS of the mercurials in the practice of dermatology is undoubted, but the choice must be made from the several different salts so as to comply with the demands of the affection under treatment. The emplastrum and ointment of mercury, the yellow oxide and its ointment, the red oxide and its ointment, the mercurous chloride and the oleate as well as the ointment of the nitrate all have select duties to perform upon the external skin. They may be chosen for treat ment of conditions affecting the eyelids or their duty may consist in relieving some more aggravating affection occupying a large tract of epidermis, they may be used to prevent contamination through the germs of the air or to assist in removing parasites that may affect the skin or manifold uses may be mentioned in which one or the other have performed cures. Internally the mercurial pill, the mercurous chloride and both the red and green iodide have innumerable uses in the treatment of disease. The poisonous qualities of some of these limit their usefulness on account of the fear entertained that some careless person may unwisely lay it around or that its application may cause fear in the minds of those who may be aware that they are using a poison. This fact contributes some theory why the mercuric chlo. ride is not of so decided advantage in the treatment of cutaneous eruptions but if carefully advised and carefully placed in the hands of some responsible person this fear is greatly diminished. It is positively injudici

ous to place any poisonous compound in the hands of irresponsible or unknowing persons whether that be a mercurial or some other preparation.

The mercuric chloride has a decided field of usefulness in the treatment of these external affections and no less may be said of it in the treatment of these by external or internal methods. As an antiseptic, I hardly believe much is necessary to be told because it has been so much used in this capacity and has performed such manifold cures and assisted or prevented the growth of germs in the effected areas that it has established its usefulness in this direction.

In using the mercuric chloride in dermatology, it may be advised either in pill, ointment or in liquid form. The dose and quantities will be men. tioned when speaking of the several affections in which it may be advised.

Externally it will be found advantageous to a greater or less extent and while it may prove useful in some cases of the affections to be mentioned it will likewise fail to produce a cure..

Pediculosis.-The ravages of the pediculus may be checked by the application of this remedy. In treating a case of this condition occupying the hairy parts, it will be wise to make use of a liquid preparation, in the strength of from one to four grains of the salt to the ounce of solution, the weaker the strength the more preferable for the first ap plication, but in those cases affecting the non-hairy regions it will be better to use an ointment so as to keep in close contact with the skin at all times, the strength should vary from one-half to about two grains to the ounce of ointment. I have found it unwise to use the mercurial ointments on the hairy parts because the parasite passes over it without touching it.

Tricophytosis.-The vegetable parasites of the skin are removed or killed by the mercuric chloride. Tinea circinata may easily be cured by its use. The strength of ointment may vary from one-half to two grains to the ounce of ointment, using either lanolin, petrolatum or ointment of zinc oxide, according to preference. This application should give a cure in a very few days if it is applied by

some competent person, as the physician himself or some nurse in whom he may have confidence. The result in the treatment of ringworm of the beard (tinea sycosis) while not positively so effective often ends in cure. Ointments are more preferable in the bearded region because of its keeping in close contact to the affected areas. The strength of ointment required to reach the desired result varies with the case but it will be found wise in all cases to first use a mild application and increase according to the demands of the case presented. Ringworm that attacks the scalp (tinea tonsurans) may be affected curatively by the mercuric chloride but in my experience the number of failures far outrank the number of cures. I cannot recommend it as a positive cure.

Tinea Versicolor.-While tinea versicolor is one of the mildest of the contagious vegetable parasitic affections of the skin it nevertheless requires in a great number of cases the strongest of parasiticidal remedies. Mercuric chloride rarely fails to effect a cure if carefully and continuously applied. One fact must be understood and that is that the underwear should either be destroyed or boiled in a solution of mercuric chloride for several days or some one of the many parasites may escape notice and cause a fresh outbreak. The strength of application may vary from one to two grains to the ounce, and then applying the solution or ointment to each and every portion of the diseased surface. Care should always be taken that not even one single small spot remains, or return. will be inevitable.

Scabies.-Cases of animal parasitic affections of the skin, such as scabies, should never be treated with so poisonous a drug as mercuric chloride, without the case is under the direct observation of the physician at all times, as in a hospital, because of the deleterious effects that may arise. I myself, never use it in these cases, but I can say that it has a curative effect.

Alopecia-Alopecia Areata.--The mercuric chloride seems to have a restoring effect in cases of loss of hair, both in the general alopecias as well as in the circumscribed varieties.

Applied to the skin as a stimulant, it has been known to effect a return of hair, or mistakes of opinion may have been induced on account of natural return. Ointments and liquids may be used in strengths varying from one to four grains to the ounce, while extreme care is given all cases. given all cases. Too much dependence must not be placed upon the drug in these affections.

Lentigo.--Chloasma.--Pigmentations of the skin may often be removed by applications of this salt, and therefore such affections as chloasma and lentigo may be given liquids in the strength of from one to four grains to the ounce, always beginning with the lesser strength until no effect is observed, and then increased until an effect is produced. Many cures will be observed with the use of mercuric chloride, if it is applied faithfully and judiciously about three or four times during the twenty-four hours.

Lichen Planus.—Some of the affections of the skin, in which nervousness is a marked symptom, are often cured by the internal use of the mercuric chloride. Lichen planus has been cured by using one-twelfth to a sixth of this drug, but the remedy must be given for some time to produce this effect. Ointments of this salt often prevent the itching that is so consequent in this affection, and the strength should be used about two grains to the ounce. I have seen many good results with the internal and external uses of this drug in this affection.

Eczema.--Eczematous affections may often receive good results by using this remedy. In those cases in which infiltration or thickening are present, its application may often be advised with benefit. Other remedies may possess this property, and may be found more advisable by

observers.

Syphilis.-It is possible that in syphilis, mercuric chloride performs the greater amount of work other than as an antiseptic. It is hardly necessary to make this assertion, because I believe every one has been taught the use of this salt in this affection, as it is in the armamentarium of every teacher in all the colleges, but they seem to lose sight