Carbonic Acid; Carbonate of acid was long ago supposed to exist in urine, although its existence in this fluid is doubted by Berzelius. Dr. Prout says that he has frequently met with this acid in urine, and is most frequently derived from the decomposition of urea, which with water is readily converted into carbonate of ammonia. Carbonate of lime is occasionally found in the urine, and is probably formed by the reaction of carbonate of ammonia on the phosphatic gaits : the urine in these cases is alkaline. Carbonate of lime dissolves with effervescence in dilute acid.
lyric frequently exists in larger quantities than natural, and is then precipitated in the urine, either with or without bases. When combined with !sues it forma what is called the " calculous sediment" of urine. The exact composition of the sediments of uric acid with bases has been the cause of much dispute. At one time all uric acid deposits were considered as combinations of the acid with ammonia. Subsequent analysis has shown that urate of soda is a very common sediment. These deposits occur either directly after the urine has cooled down to the temperature of the external atmosphere, or some hours after. In the latter case the production of some other acid by decomposition is the cause of the precipitate. These deposits may not alone occur from increase of uric acid in the urine, but also from a decrease of water in the urine and a relative increase of uric acid. The formation of other acids may also cause this. Sometimes the uric acid is depo sited without any base, and then assumes its characteristic forms. This may arise from excess of uric acid, but it may also arise from the formation of such acids as the sulphuric, phosphoric, hippuric, lactic, oxalic, or other acids.
Phosphoric add forms sediments of the ammoniaco-magnesian phos phate, the phosphate of lime, and the phosphate of magnesia. The cause of the deposit of the ammoniaco-magnesian phosphate is tho decomposition of the urea. The carbonate of ammonia thus produced lessens the acidity of the urine, and the ammonia partly combines with the phosphate of magnesia. As soon as the acidity declines the ammoniaco-magnesian phosphate is deposited with phosphate of lime.
If the urine become alkaline from potash or soda, and not from ammonia, then the phosphates of lime and magnesia are thrown down. This occurs after eating much vegetable food, or after the carbonates or the mixed alkalies have been used for a length of time as medicines. This group of deposits often become the source of stone in the bladder. [CAtousrs.]
The next group of abnormal deposits in the urine are those which have never been dissolved in the urine, and which fall when the urine is allowed to stand. These are mostly organic, and are detected chiefly by the aid of the microscope.
Blood is often poured out in abundance from the mucous membrane lining the urinary passages, and is generally diffused through the urine, or is passed entire. In other cases small quantities of blood are passed mixed with pus or mucus, or alone, after the urine has been voided. When large quantities of blood are passed, especially without pain, it is probably a simple exudation from some part of the mucous surface of the urinary organs ; on the other hand, when the blood is mixed with pus or mucus, and passed with pain, it denotes ulceration of the kidney or bladder, and may be combined with the existence of a foreign body in the bladder. Dr. Willis, and other writers, quote several authorities to show that htematuria is endemic in some countries. M. Chapotain, for instance, informs us that in the Isle of France children from their infancy are liable to hmmaturia without suffering any pain from it, or its appearing to prejudice their general health. M. Salesse, a native of the Isle of France, and now a practitioner of medicine there, states that three-fourths of the children are affected with hxmaturia at one time or another. In these cases the bloody urine is generally observed to alternate with that which is chylous or oleo-albuminous. During the invasion of Upper Egypt by the French, many of the men suffered from an epidemic hiematuria.
When blood corpuscles are present in the urine, of course albumen is also there. It is sometimes a question whether the albumen is greater in amount than can be accounted for by the blood or not.
Pus is often found in great abundance in the urine. Upon standing, the pus subsides to the bottom of the vessel, in a state more or less pulverulent, and the fluid resumes its transparent character. If pus be present as well as mucus, the former is found lying on tho latter, and presents a much yellower tint ; it is also quite opaque, whereas mucus is more or less transparent. A ready test for determining whether the deposit from the urine be of a purulent nature, is to add liquor potassm to the sediment collected in a phial or test tube. If it be purulent, it will, on agitation, form with the alkali a transparent viscid compound.