indiscriminately to rot and vitiate the atmosphere; the privy, stable and pig-sty, active manufactories of pestilent exhalations; surface water allowed to accumulate until the house itself is saturated with health-destroying damps.

The residents of the average American village sadly need enlightening on sanitary subjects. In many instances they are innocent of the first principles. Where lies the fault? Indisputably with the supposed conservators of public health, the physicians.

The aim and object of this brief paper is to rouse the members of the American Institute to a realization of the weight of responsibility which rests upon them in connection with this vital question of sanitary reform. You, gentlemen, are recreant to the duties you owe society if you do not make yourselves familiar with the whole subject, and do your best to disseminate correct views. You can speak as having authority, for this matter lies peculiarly within the physician's province. Do not hesitate to agitate the subject in the public prints. Brief and pointed articles will instruct and convince more rapidly, perhaps, than anything else. They should be plain and practical. The points at which we have hinted in preceding remarks may be carefully elaborated to suit each village or agricultural community. "Knowledge is power" in more ways than one. The physician who carefully informs himself on the avoidable causes of disease, and who steps fearlessly to the front and instructs the community in which he resides, will, in the very nature of things, command the gratitude and respect of his neighbors, so true is it that the conscientious discharge of duty brings its own reward.

IV.

THE ANALYSIS OF URINARY DEPOSITS.

BY C. P. ALLING, M.D., BRADFord, Penna.

THE subject of analysis of urinary deposits does not receive from physicians the attention that its importance merits. When it is remembered that the entire amount of the solid portion of waste tissue is eliminated by the kidneys, and makes its exit from the body as effete product in the urine, it shall be readily seen that a careful examination of this excretion must give a valuable key to the location, nature and extent of any destructive process occurring within. Such is true in fact, and the diagnosis of many forms of disease may be accurately determined by analysis of the urine without further examination of the case. Some diseases, as oxaluria and Bright's disease of the kidneys can be recognized in no other way, at least in time to be of benefit to the patient.

The microscope furnishes the most easy and certain means of determining the various substances deposited in the urine. Thus, spermatozoa are recognized by their oval nuclei and elongated flagella; blood-discs by their circular and cup-shaped appearance; pus-globules and mucus-corpuscles by their spherical form and granular contents; chloride of sodium, oxalate of lime, ammoniaco-magnesian phosphates, and the like, by the size and shape of their crystals, etc. Without the instrument but little could be known of the distinctive forms of these various substances.

A thorough and complete analysis of the urine, however, re

quires something other than simple examination with the glass. In order to precipitate the substance under consideration it is often necessary to treat the specimen with some suitable chemical reagent. Earthy phosphates being held in solution in acid urine, the addition of an alkali, as aqua ammonia, is required to obtain the precipitate. Addition of a mineral acid favors the precipitation of uric acid.

Many of the ingredients sought for in disease are also constituents of normal urine, and the value of the examination often rests upon the relative proportions in which they are found; hence the complete analysis requires a microscopical examination and also a chemical and quantitative analysis.

As being so intimately connected with the subject of microscopy proper, I ask your attention to a brief and practical consideration of this last, namely, quantitative analysis of the

urine.

This examination is best accomplished by the volumetric method, or the method by titration, which depends upon the employment of certain solutions, the strength of which has been carefully ascertained, by aid of which other substances in solution may be accurately determined. The French make use of what are termed "normal "solutions, which are composed of the atomic weight of the reagent expressed in grams, dissolved in a liter of distilled water.

A very convenient plan, however, is to use what may be termed "standard solutions," the formulæ for which may be varied to suit the convenience of the manipulator. The best burettes are marked with a scale accurately graduated from 0 to 200 grains, and it is well, after selecting the reagent for testing any given substance, to make the solution of such strength that 200 grains shall neutralize or precipitate exactly one grain of the substance under examination.

Example.-Titration for uric acid: Use a solution of permanganate of potash containing 2.1 grains to 1000 grains of distilled water. Having precipitated the uric acid and set aside for crystalization and precipitation, pour off the supernatant fluid. Wash the crystals and redissolve in a solution of potash strongly acidulated with sulphuric acid. Place a beaker con