UNUSUAL CONDITIONS OF THE URINE AND THEIR DETECTION.
The Examination of the Urine.—A care ful examination of the urine is capable of yield ing very important indications of the state of health of a person. Sometimes the presence of a disease, quite unsuspected, is revealed by it, and it is a very common thing for physicians, unable because of vague symptoms to decide what is wrong with a person, to have all doubts set at rest by examining the urine. Moreover, such an examination frequently affords the most reliable evidence as to the progress a sufferer is making, whether towards recovery or towards a more serious state of disease. It will, therefore, not be out of place in a work specially intended for the guidance of persons not acquainted with medical science, to give a brief account of the main steps in such an examination. Besides, such an account will help to show that the modern practice of medi cine rests on a really scientific basis, and is not a mere rule-of-thumb, hap-hazard procedure. If this were fully realized by the public, the writer is confident it would lead to them taking greater care to place themselves, when the state of their health demanded it, in the hands of educated medical men, and would impress them with the risks they run in seeking the counsels of quacks and impostors.
The appearance of the urine should first be regarded. It ought to be quite clear and trans parent, depositing after some time a light cloudy precipitate consisting of mucus from the urin ary passages. The urine may grow muddy and cloudy when it has become cool, or soon after being passed. A small quantity should be placed in a test-tube or metal spoon, and gently heated over a gas or spirit-lamp flame ; if it clears up, the deposit is urates. This is due frequently to feverish states, and to disturb ance of the digestive system. If the gentle heat makes it more cloudy, a few drops of common vinegar should be added. If it then clears up, the deposit has been phosphates, and indicates that the urine has been alkaline. It should be noticed that if the urine has stood for sonic time this may have been due to de composition in the mine. For urine when passed should be acid, but after standing for some days it undergoes decomposition and be comes alkaline, when phosphates are precipi tated, making it muddy. It is only when phos phates appear in freshly-passed urine, or in urine quite recently passed, that they are sig nificant. Then they indicate decomposition occurring in the bladder, or an altered con dition of blood and nutrition, requiring further investigation.
The nature of deposits other than those men tioned is determined by means of the micro scope.
The colour of urine varies with the degree of its concentration. That which deposits urates is high-coloured. Other very high-coloured urines should be tested for blood and bile as mentioned further on.
The quantity of urine passed in 24 hours is between 21- and 3 pints. It varies with the
quantity of water taken, and with the activity of the skin, being less when the skin is active, as in warm weather, when it is of a darker colour, and greater when the skin is less active, as in cold weather, when it is pale and limpid. Nervous persons pass a large quantity of clear urine of low specific gravity (see POIXURIA, p. 407). When a constantly large quantity of urine is passed, it ought to be examined for sugar (see DIABETES, p. 407). Persons ought to distinguish between passing a large quantity of urine and passing it often. Irrita bility of the bladder will cause frequent desire to pass water, and the person may conclude that an unusually large quantity is voided. This is settled by collecting all that is expelled in 24 hours and measuring it. A constantly small quantity ought to lead to investigation for kidney disease.
The determination of the specific gravity of the urine is the next step in a systematic examination of the fluid. This is done usually by means of an instrument called a urinometer, shown in Fig. 162. It consists of a glass bulb of an oval shape, loaded at one end by a small qua:ntity of mercury, and prolonged, at the other end, into a stem which has a series of marks on it at regular intervals, each mark having a number attached. The instrument is so structed that if it be mersed in a tall glass tainingdistilled water it will sink in the water for a tain distance and then float with the stem upright. The water will reach to the top score on the stem, marked Q Now if 10 ounces of common salt be dissolved in 1000 ounces by weight of distilled water, and if the tall glass be nearly filled with this tion, and the urinometer placed in it, it will sink till the stem is immersed up to the mark 10, indicating that there are 10 parts of solid matter in every 1000 parts of the fluid. pose now the tall glass be nearly filled with urine, and the urinometer be placed in it, the level to which the stem is immersed in the urine can be read off, and thus the quantity of solid matters ascertained. If the urinometer floats at the mark 20, that means that in every 1000 parts of such urine there are 20 parts of solid matters dissolved, and so on. The specific gravity of urine is usually about 1020. But it varies with circumstances. Thus if the skin be very active or the weather hot, a large quantity of water will escape by the tion, the quantity of water expelled by the kidney will be less, and the urine will contain a greater quantity of solids in proportion to its liquid parts. Again, if a large quantity of water or other dilute fluids be drunk, more water will escape from the kidneys and the urine will be more dilute. In order not to be misled by temporary variations one ought to collect all the urine passed in 24 hours, mix it, and take a sample of the mixture.