These glasses should be graduated upon at least 50 c.c. every division, of which there ought to be 40, equal to a measure on the whole of 2000 c.c. Graduation upon single fluid ounces up to fifty or sixty serves the same purpose. The physician on coming to the bedside would then be enabled to inform himself by a glance of the total quantity of urine collected; and, if none were lost, of the whole bulk discharged.

In some hospitals the ancient urinal is still in use; its only advantage over the ordinary vessel is its being made of glass; its shape is much less convenient than that of the glasses described above, which admit of the discharge of urine in the recumbent or any other posture.

In many cases the difficulties in the way of collecting the whole of the urine discharged in twenty-four hours are very great. Any one of my readers will easily find them out by trial upon himself; with women and children they are still greater. Unless a special apparatus be employed, a certain loss at every motion is nearly unavoidable. To empty the bladder when the rectum is pressing is difficult, and frequently impossible, or interferes with the function of the bowel, and then becomes injurious to health. But the quantities so lost are very small indeed when compared with the total collected by all available means, and may safely be made up for by an estimate.

The matter becomes more embarrassing in cases of severe illness, where, unfortunately, with the importance of the indications to be derived from the quantity and quality of the urine, the obstacles to a complete collection become greater. Patients in a delirious, or unconscious, or paralysed state will retain or pass unconsciously a part or the whole of their renal and alvine excretions. Here we must estimate the losses from known and collected quantities in proportion to time and from the evidence to be derived from inspection. Allowing 20 per cent. for error in the estimate, the known quantities will reduce this error to 10 or 5 for the whole amount in the worst cases.

In this manner the practical man may obtain the nearest possible approach to truthful observation. Unless, however, all the cautions are employed, we would strongly recommend that too nice conclusions should not be based upon such incomplete observations, though they even give to the thinking practitioner points of evidence to which he may append his reflections, and which may be taken into account in forming the prognosis of a case, or in tracing out a plan for therapeutical proceedings.

TOTAL QUANTITY OF URINE DISCHARGED IN A GIVEN TIME.

Any attempt to make a quantitative analysis of the urine for the purposes of physiological or pathological research must be based upon the knowledge of the total amount of urine discharged in a given time. It is the neglect of this point which makes all analyses useless which are calculated upon thousand parts of urine, regardless of the time in which it was passed. Hence we must, though with regret, exclude from consideration, by this sweeping objection, the vast number of analyses made and published till within a period of three or four years ago. And not only on this ground are these analyses excluded, but the want of accuracy in the methods makes them so much lost labour. Some authors, though perfectly well aware that in all cases where any approach to accuracy in the determination of the specific gravity is required, an average sample from the urine passed in twenty-four hours into the same vessel must be selected, -have yet formed no settled idea of the necessity of knowing the whole amount of urine discharged during the twentyfour hours. It could have been only by losing sight of this point that they recommended the determination of the average density of the urine from the density of a mixture of the urine passed immediately before going to bed, and of that voided on rising in the morning. But of what use is it to know density at all, if from the density we cannot calculate the whole of the solids discharged in a given time? For this we must know the whole amount of urine.

But

We may either collect the whole bulk of urine passed in twenty-four hours, or in every single hour, or in as many portions of the twenty-four hours as convenient. it should always be expressed in a value calculated upon the twenty-four hours, or upon every single hour. In many chronic and acute diseases we must collect and analyse the urine for several days in succession, in order to arrive at a correct conclusion upon the average condition.

The amount of urine is best determined by measuring in the graduated urinals; or, if more accuracy is desirable, in high graduated cylinders of a capacity varying from 500 c.c. to 2000 c.c., or from 10 to 50 fluid ounces. The large cylinders have marks for every 10 c.c., and a practised eye will easily estimate one fourth of a division; it is, therefore, possible to determine the entire quantity to within 25 c.c. in a very short time. The small cylinders, which are to serve

for measuring the quantities of urine of a shorter period, say one hour, should be divided into single cubic centimetres, or into fluid drachms.

Both descriptions of cylinders must be provided with lips for pouring out their contents. Their upper borders must be ground in an horizontal plane, so that a glass disc, with the assistance of a little tallow, will make an air- and water-tight cover, and prevent all loss by evaporation. The foot of the cylinder must be ground so correctly that the vessel may be perfectly perpendicular when standing on a horizontal plane. If the latter is not at hand, a tripod or disc with elevating screws and two spirit levels will be the easy means of placing the cylinders in a perfectly horizontal position. These tripods are easily obtained, as they are now commonly used in photography.

If it is desirable to know the weight of a certain bulk of urine, it is only necessary to multiply the number of cubic centimetres found by measure into the figure expressing the specific gravity; the result will give the quantity in grammes, thus

In valuing the physiological effects of the variations of the discharge of urine, the fact must always be borne in mind that the water discharged in the urine is only a part of the water excreted by the whole body. According to our best estimates, one half of all the water ingested into the body goes away by the kidneys; the other half by the lungs, the skin, and the fæces together.

I have considered it useful to add some observations on the total quantity of urine discharged by healthy individuals, to the observations already existing. They were made upon two individuals; the one, A, a man twenty-eight years of age, and weighing 70 kilogrammes; the other, B, a man twenty-eight years of age, and weighing 72 kilogrammes.

A, æt. 28, weighed 70 kilogrammes. Quantities of urine from 12 midnight to 12 midnight, twenty-four hours each.

Seventy-six days, with one interruption of twelve days. and one of ten days.

The quantity of urine discharged by 4 is therefore 1950 c.c. per day, as the average of seventy-six days. Maximum, 2920 c.c. Minimum, 1049 c.c. The minimum of 650 c.c. I must assume as abnormal; the individual on that day had a cold and headache.

B, at. 28, weighed 72 kilogrammes. Quantities of urine from 12 midnight to 12 midnight, twenty-four hours each.

Fifty-seven days, with five interruptions, of eight, one, one, one, one day respectively.

The quantity of urine discharged by B is therefore 1723 c.c. per day, as the average of fifty-seven days. Maximum, 2655 c.c. Minimum, 1040 c.c.

The quantity of urine discharged in twenty-four hours by healthy adult persons has been determined by various other observers. The results of their observations, together with the results of my own, are arranged in the following table