but, if a long time elapses before a deposit is apparent, it indicates the presence of only a small quantity of the salt. In all cases of albuminuria either nitric or muriatic acid should be employed, as nitric acid precipitates albumen.

The following is Dr. Golding Bird's diagnosis of uric acid deposits: "When heated in the urine, the uric acid deposit does not dissolve, the crystals merely become more opaque. They generally become more distinct, from the solution of the urate of ammonia, which is frequently mixed with them, and sometimes completely conceals them from view. Hence the best mode of discovering this deposit is to warm the urine, when turbid from excess of urate of ammonia, in a watch-glass: the acid becomes visible at the bottom of the glass as soon as the urate dissolves."

CREATINE.-General Appearance. In its crystallized form it is a colorless, transparent, and glossy substance.

Chemical Composition.-C. H9 N3 04 + 2 Aq.
Specific Gravity.-1.35 to 1:34.

Quantity in Normal Urine, and whence derived.-An excrementitious substance, derived from the muscles; excreted from the blood by the kidneys, and passing thence into the bladder and out of the body; a constant constituent of the urine, but present in very small quantities.

Quantity Passed in Health in Twenty-four Hours.-Thudicum places the average quantity passed in twenty-four hours at 0·305 grammes.

How Increased or Diminished.-The quantity is increased by muscular action, febrile conditions, and whatever produces rapid metamorphoses of the muscular tissues. The causes which tend to diminish it are muscular inactivity, anæmic conditions, feeble action of the circulatory and respiratory systems.

Mode of Detection.-First evaporate the urine to a dry extract, then, with a solution of ammonia, dissolve out the creatine, and finally evaporate the solution of ammonia, leaving the creatine in a crystalline state. Under the microscope these crystals present themselves in various forms, but may be readily distinguished by accustomed observers. (See Hassall on Urinary Diseases.)

CREATININE-General Appearance. Creatinine erystallizes in irregular groups of very transparent and light-colored crystals. They may be distinguished from those of creatine by their lack of lustre. Creatinine is usually present in the urine in a free state. Much of it is supposed to be derived from the conversion of creatine into creatinine during its passage through the urinary organs, and after the urine has been evacuated. It is more

Chemical Composition.-Formula: Cs H7 N3 02.

soluble in water than creatine-one part dissolving in 11-5 parts of water at 60° F. Its chemical character is almost identical with that of ammonia.

Specific Gravity.-The specific gravity of the crystals is about equal to 1.35.

Proportion in Normal Urine.-Always greater than that of creatine, from whence it is derived.

Quantity Passed in Twenty-four Hours.-The average quantity passed in twenty-four hours in health, varies, according to the experiments of Thudicum, from 561 to 9.66.

From whence Derived.-An excrementitious substance, derived in part from metamorphosed muscular tissue, and in part from the conversion of creatine into creatinine after the urine has been separated from the blood by the kidneys.

Causes which Increase or Diminish It.-Like creatine, it is increased by those causes which effect a rapid disintegration of the muscular tissues, and diminished by those conditions which retard those muscular transformations.

Mode of Detection.-Same as for that of creatine.

HIPPURIC ACID.-General Appearance. In its crystalline state it is in the form of "delicate silky needles or rhombic prisms;" taste bitter; sparingly soluble in cold, but more readily in boiling water, and still more soluble in alcohol. Supposed by Liebig to be a constant constituent of normal urine, in about the same proportion as uric acid; but the observations of Duchek do not confirm this opinion.

Chemical Composition.-Formula: N. C. 18. H8. 05 × Aq. It is readily decomposed by nitric acid, and converted into benzoic acid. It enters into combination with several alkaline and earthy bases to form the hippurates.

Quantity in Normal Urine.-Much diversity of opinion prevails upon this point. According to Liebig, uric acid and hippuric acid are present in healthy urine, in about equal proportions; while Hoesle and Duchek deny that the latter is a normal ingredient of this secretion.

Quantity Passed in Twenty-four Hours.-The quantity secreted depends much upon the habits of the individual and the kind and quantity of food consumed. But the average amount may be placed at from 0-40 to 0.50 in twenty-four hours.

principally from the nonBird supposes that it may

From whence Derived. It is derived nitrogenous elements of the food (Liebig). owe its origin to an undue retention of carbon in the blood, from defective action of the lungs and liver..

How Increased or Diminished.-Increased by rest and by the uso of fruits, like pears, plums, cherries, apples, &c., and diminished by ac

tive exercise in cold air and rigid abstinence from stimulants, coffee, and meats.

Mode of Detection.-Turbid urine indicates the presence of considerable hippuric acid, while clear urine usually contains but a small quantity. For other methods of detecting it see "Thudicum on the Pathology of the Urine," p. 143.

Coloring Matter of Urine.—Thudicum gives the name of uræmatine to this substance, from the supposition that it is "derived from the pigment of the blood or hæmatine." In a dry state it is of a deep red color, and it is this substance which communicates to urines their various tints. Scherer supposes that it is derived from the decomposition of blood corpuscles. It is composed chiefly of carbon. But little is known at present of its exact character-its derivation, chemical reactions, &c.; but it is doubtless an effete and excrementitious substance.

FIXED SALTS OF THE URINE.-Sulphates. Of the fixed salts of the urine the sulphates of potassa and soda are the most abundant. The average quantities of each in 1000 parts of urine are as follows, according to Berzelius: sulphate of potassa, 371; sulphate of soda, 3-16. A small quantity of pure sulphur is also present in most healthy urines. They are derived in part from the metamorphoses of the tissues.

Phosphates.-Berzelius gives us the following proportions of these salts as pertaining to normal urine: phosphate of soda, 2.94, and phosphate of ammonia, 1-65, in 1000 parts of urine. Traces of phosphates of lime and magnesia are also always present in normal urine. Free phosphorus is said to be a constant constituent of healthy urine. Derived chiefly from disintegrated muscular, brain, and nervous tissues, and from food and drinks. Increased by mental activity and cerebral irritation.

Chlorides.-These occur in normal urines in the form of chloride of sodium and potassium-the proportion of the former to 1000 parts of water being 4:45, and of the latter a trace.

Minute quantities of the following substances are likewise found in all normal urines: silica, free lactic acid, fluoride of calcium, hydrochlorate of ammonia, acetate of ammonia, albumine, gelatine, and benzoic acid.

2. BRIGHT'S DISEASE OF THE KIDNEY.

SYNONYMS.-Albuminuria.-Acute desquamative nephritis. (Johnson.)— Renal cachexia. (Wood).—Albuminous nephritis.—Granular degeneration of the kidneys.— Fulty degeneration of the kidneys.-Uramia.

In 1837 the attention of the medical public was first seriously directed to this malady by Dr. Bright, of London. Although a few previous

writers had vaguely alluded to the disease, and thrown out some hints with regard to its probable nature, yet to Dr. Bright belongs the credit of having first presented to the profession a systematic and moderately accurate description of the symptomatic and pathological phenomena of the disease. We adhere to the term "Bright's disease" to designate the malady, because not one of the other names applied to it conveys a just impression of its actual nature. The prime cause, the ultimate essence of the malady is not located in the kidneys, but in the blood itself, in the form of retained effete matter from diseases, from the presence of noxious drugs, from checked perspiration, &c. So long as these poisons remain in the blood, its normal condition is disturbed, and the entire organism suffers. Nature, always kindly in her instincts, always on the qui vive to sustain the integrity of the delicate organization over which she has been placed in charge by the Great Architect, strives to eliminate all disturbing agents through one or more of the natural emunctories of the body; and she always selects the most appropriate channels to throw off each deleterious substance. As examples we cite the following:

When the poison of variola has infected the blood, the skin is selected as the eliminator, and the energies of the system are concentrated to throw out upon this part, suppurating pustules loaded with the escaping poison of small-pox. The copious discharges from the pocks usually suffice to relieve the blood of its morbid constituent, and thus enable the system to return to a normal state. But in some instances the pustules fail to perform their full duties as eliminators, the kidneys are called into requisition as auxilliaries, and, as a consequence, renal inflammation is sometimes the result.

In the case of scarlatina poison, the most important eliminators are the skin and the mucous membrane of the throat and intestinal canal. When the poison is intense, and the natural recuperative forces are feeble, these parts fail to perform their offices efficiently, and an extra amount of labor devolves upon the kidneys. During the passage of this poison through the tubuli uriniferi, an inflammatory congestion is produced, which prevents the Malphighian corpuscles and the epithelial cells of the tubes from separating from the blood normal urine, and permits the passage of albumen, fibrin, and other abnormal constituents.

In measles, erysipelas, and other cutaneous disorders similar conditions not unfrequently obtain. So likewise in many other conditions of the system; in scrofula, psora, constitutional syphilis, the presence in the blood of poisonous substances, like mercury, phosphorus, turpentine, copaiba, and other drugs, retained perspiration from the action of cold, &c., the kidneys may become inflamed in their efforts to eliminate these noxious influences. During this process of elimination, if the

poison is directed towards the skin, eruptions and cutaneous inflam mations of various kinds may result; if it is attracted to the bowels a diarrhoea will occur; if to the liver, hepatic inflammation will ensue; if it passes out of the blood through the kidneys, we shall have the usual phenomena of acute desquamative nephritis, with a rapid production and detachment of the epithelial cells of the convoluted tubes, inflammation of the Malphighian bodies, exudation of serum, fibrin, &c.

When renal inflammation results from any of the causes cited, it can only be regarded as an effect of the action of the passing irritant. To this effect medical men at present direct their chief attention, almost regardless of the more deep-seated and vital derangements which originate the complaint. In a therapeutical point of view the distinction we have described is important in guiding the medical man to a more comprehensive and efficient mode of treatment.

Bright's disease may originate from other causes than those enumerated. In our own practice we have on several occasions met with both acute and chronic forms of the malady, which were clearly traceable to irritable bladder, and other chronic affections of this organ. In several of these instances incontinence of urine (especially nocturnal) had existed for years previously to the renal attacks. It is highly probable that long-continued sympathetic irritation of the kidneys from urethral strictures, cystic calculi, and other causes of similar character, may eventually give rise to the complaint under certain circumstances. In a monograph recently published in Paris, entitled "La Fievre Jaune de La Nouvelle-Orleans," by our friend A. J. F. Cartier, M. D., it is stated that albumen is often found in the urines of yellow-fever patients, during the second and third stages of the malady. Dr. Cartier has personally verified this statement in several instances. Does not this fact go far to prove that the immediate cause of yellow fever is a blood-poison, introduced from without, the tendency of which is to produce a rapid decomposition of the blood, with consequent functional derangement of nearly all the organs, and finally exudation of serum into the stomach, black vomit, general prostration and death, unless the poison be eliminated during the first stage of the malady, through the pores, the kidneys, and other emunctories? A confirmation of this view consists in the fact, that when the cutaneous, renal and hepatic se cretions are kept in uniform and steady action from the outset of the disease, recovery invariably results.

Albuminous urine has often been detected in cases of cholera as phyxia, and in ship, hospital and other typhoid fevers. In these examples, as in the cutaneous maladies enumerated, the blood is contaminated with specific morbid poisons, and during the reaction of the vital force to eliminate them, the kidneys become inflamed.

One of the most common and characteristic phenomena connected