portions of calculi containing a large proportion of organic matter are heated on platinum foil, they give off the odor of burnt horn and burn with a yellow flame. Concretions containing crystals of hematoidin are occasionally seen. These crystals are most commonly seen in fibrin concretions, or in those calculi that have formed in the presence of a considerable amount of blood. PROSTATIC CONCRETIONS. Concretions emanating from the follicles of the prostate are occasionally discharged with the urine. They usually have a laminated nucleus consisting of amyloid bodies (corpora amylaceae) about which is deposited a mixture of ammonio-magnesium phosphate and calcium phosphate. They do not, as a rule, produce symptoms until they have attained a large size; prostatic concretions of large size are, however, rare. CHEMIC EXAMINATION OF URINARY CALCULI. Before beginning the chemic examination of a calculus, its size, shape, color, and density should be observed, as these properties often suggest the probable composition of the concretion. Since a calculus may consist of alternate layers of two or more substances, it is first necessary to make a section through the center of each layer of the stone by sawing, in order to determine the composition of each layer. If several different layers are found, it is essential that a portion of each layer be subjected to chemic examination; that portion to be tested should always be in the form of a fine powder, which can be obtained by scraping a very small amount of the stone from its cut surface by means of a knife-blade, or by placing small particles of the calculus in a mortar and grinding them to a powder with a pestle. If the section of the stone is found to have a homogeneous appearance, it is only necessary to examine the sawdust; it is, however, advisable to make a separate examination of the nucleus in every instance, since this portion of a concretion is subject to marked variation. The chemic examination is best conducted in the following manner: 1. Preliminary Examination.-Heat on platinum foil: Albumina flame with odor of burnt horn. Urostealith a flame with odor of shellac and benzoin. Cystin = a blue flame with odor of SO,. Xanthin and uric acid = char without a flame. = a residue soluble Calcium carbonate original powder soluble in acetic acid with effervescence. Calcium oxalate original powder insoluble in acetic acid. Silica residue insoluble in HCl. Murexide Test for Uric Acid.-Original powder + HNO, and evaporate = pink residue + NH2OH color uric acids and urates. = purple Original powder + HNO, and evaporate + KOH violet color, which disappears on heating = uric acid. Violet increases on heating : xanthin. 2. Systematic Examination.-Presence of uric acid. shown by (1). Boil in H2O and filter. A. = Filtrate HCI. Let stand 24° crystals of uric acid. Bases in solution. Concentrate. Calcium urate one drop of solution + solution ammonium oxalate = crystals calcium oxalate. = Magnesium urate one drop of solution + NH2OH + Potassium Urate.-Evaporate solution and ignite on mica. Calcium carbonate = soluble with effervescence. Filter + NHOH precipitate of calcium oxalate, calcium phosphate, and ammonio-magnesium phosphate. Wash. Calcium oxalate = insoluble in acetic acid. Filter ammonium oxalate to filtrate. Calcium phosphate gives precipitate of calcium oxalate. Filter NH OH to filtrate - precipitate of ammoniomagnesium phosphate. PART II. DIAGNOSIS. CHAPTER VIII. DISTURBANCES AND DISEASES OF THE ACTIVE HYPEREMIA. Active hyperemia-active congestion-is essentially not a disease of the kidneys, but a disturbance of the functions of these organs. This condition is invariably due to the presence of some irritant that is within or is passing through the kidneys, or to some alteration in their circulation-in other words, it is always secondary in its nature. Causes. The causes of active hyperemia may be divided into three general classes: I. Any general disease or disturbance, which is not primarily renal, but which may cause a change in the renal circulation, as in severe nervous diseases, notably delirium tremens and acute mania; also in other serious affections that act by causing a change in the pressure of the blood in the renal vessels. Exposure to cold and wet may set up an active hyperemia of the kidneys or an acute nephritis. The reason for a renal disturbance under such circumstances probably is that the superficial blood-vessels and the capillaries of the skin suddenly contract, due to vasomotor changes, congesting the internal organs, and, since the function of the skin is interfered with, the renal congestion is augmented by the necessity for increased activity of the kidneys. II. Irritants Within or Passing Through the Kidneys. These may be divided into two distinct classesviz., insoluble and soluble. (a) Insoluble Irritants.—These are crystalline substances that may be separated from the urine in the kidneys, and may set up a mechanical disturbance in the renal tubules— e. g., uric acid, acid ammonium or sodium urate, calcium oxalate, acid calcium phosphate, and cystin. (b) Soluble Irritants.—Of these there are— 1. The toxines, which are soluble poisons formed and eliminated during the progress of disease. Their irritating effect is especially seen in the acute diseases-viz., pneumonia, typhoid fever, erysipelas, measles, scarlet fever, diphtheria, acute rheumatism, acute miliary tuberculosis, cerebrospinal meningitis, malaria, etc.; and not infrequently in chronic diseases, such as pulmonary tuberculosis, chronic rheumatism, chronic malaria, etc. Irritant toxines may also be formed in the intestines as a result of faulty processes going on there. These are absorbed by the blood and eliminated by the kidneys, causing an active hyperemia. This is especially seen in children who are suffering from diarrhea or an enterocolitis. Toxines may also be formed in those acute and chronic local diseases that are attended with suppuration, notably urethritis, prostatitis, vesiculitis, bone diseases, abscesses (from which there is absorption), and diseases of the female genitalia, the disturbing element being a toxine that is absorbed from the seat of the disease by the blood and eliminated by the kidneys. 2. Drugs.-The elimination of any irritating drug, such as arsenic, lead, mercury, cantharides, salicylic acid, potassium chlorate, phenol and its compounds, volatile oils, etc. 3. Concentrated Urine.-Not infrequently the passage of a concentrated urine sets up an active hyperemia that varies in intensity from a very mild condition to one that is quite severe. It is especially seen if the urine has been in a state of concentration for a long time. An active hyperemia from this cause rapidly disappears when the patient is given plenty of diluent drinks, the urine becoming diluted and less irritating. 4. Bile. This substance acts as an irritant in its way through the kidney. It is obvious that the merest trace of bile would not, as a rule, produce more than the slightest active hyperemia, whereas larger amounts generally set up a more marked form of this disturbance. 5. Sugar.-What has been said of bile may also be credited to sugar. The author has yet to see a urine containing bile or sugar-especially if one or the other were present for more than a day or two and in more than the slightest trace-where there was not evidence of an irritation of the kidneys. III. Irritants Extending Upward from the Lower Urinary Tract. It is not uncommon to have a gonorrheal inflammation extend upward from the urethra and bladder, and involve the straight or collecting tubules of the kidney. The same danger exists in an inflammation of the bladder from any other cause. In case there is some obstruction to the outflow of urine, as by a urethral stricture or an enlarged prostate, the collecting tubules may dilate, and finally result in a “surgical kidney." Various bacteria, more especially tubercle bacilli, whether coming from the lower urinary passages by extension or by way of the blood-vessels, may set up a focal active hyperemia of the kidneys. The disturbance is principally confined to the pyramidal portion with more or less evidence of extension into the cortical portion of the kidney. Reference will again be made to this under the heading of Tuberculosis of the Kidney, Character of the Urine.-This varies as the cause: e. g., if the hyperemia is due to the elimination of toxines that are produced in the course of an acute febrile disease, we will generally find a highly colored, concentrated urine, whereas if the cause of the irritation is not accompanied by fever, the urine may have about a normal concentration, or it may be dilute. It is, of course, impossible to give the characteristics of the urine that will apply in every case of active hyperemia, yet a few general rules may be laid down concerning the average urine in this disturbance. Quantity in Twenty-four Hours.-Usually less than 1500 c.c.; average, from 800 to 1200 c.c. It may be as low as 300 or 400 c.c., and may exceed 1500 c.c., but only for a short time. Color. Normal or high. Not infrequently it is paler than normal. It may be slightly smoky (usually seen, however, in severe active hyperemia, or catarrhal nephritis). (See p. 286.) |