many inflammatory diseases the quantity of fibrin appears to be increased. In diabetes, sugar may usually be detected in the blood; while in jaundice the presence of bile may be demonstrated. Microscopic Examination of the Blood.-If a drop of blood be placed under the microscope, and examined with a quarter of an inch object glass, the red globules will be seen as a multitude of pale, red, round, bi-concave disks having a tendency to turn upon their edges, and to arrange themselves in rolls like rouleaux of coins; a very few white corpuscles, irregular in form, granular on the surface, and rather larger than the red globules will also be readily distinguished. Long maceration in serum or in water will frequently cause the red globules to diminish to half their size in bulk, and to present a perfectly spherical slightly colored body. Strong acetic acid dissolves them rapidly. Acetic acid renders the external cell-wall of the colorless corpuscles very transparent, and also brings the nucleus into view, consisting of one or two round granules. In leucocythemia-as described by Dr. Hughes Bennett-the colorless corpuscles become much increased in quantity, so that, instead of two or three being seen in the field of the microscope at the same time, some thirty, forty, or more become visible. To Examine Stains of Blood.-To discover whether a certain stain consists of blood, it must be moistened with some fluid having a specific gravity of 1040 or 1050-white of egg will answer very well-scraped off the material holding it, and examined microscopically with a quarter of an inch object-glass; blood-corpuscles will be rendered distinctly visible if the stain consists of blood. Dr. Garrod's Plan of ascertaining the presence of an Abnormal Quantity of Uric Acid in the Serum of the Blood.-From the researches of Dr. Garrod, I entertain but little doubt that the presence of an abnormal quantity of uric acid in the blood-such a quantity as is capable of being demonstrated-is a pathognomonic sign of gout; and that, consequently, where the diagnosis rests between gout and rheumatism, the presence or absence of this acid from the circulating fluid will decide the question. Take from one to two fluid drachms of the serum of the blood, and put it into a flattened glass dish or capsule; to this add the strong acetic acid of the London Pharmacopoeia, in the proportion of about six minims to each fluid-drachm of the serum. A few bubbles of gas are generally evolved at first; but when the fluids are well mixed, two or three fine threads, or one or two ultimate fibres from a piece of unwashed huckaback, are to be introduced. The glass is then to be put aside in a moderately warm place--as on the mantelpiece in a room of ordinary temperature—until the serum is quite set and almost dry, the time required varying from eighteen to forty-eight hours. If the cotton fibres be then removed and examined microscopically with an inch object-glass, they will be found covered with crystals of uric acid, if this agent be present in abnormal quantity in the serum. The crystals form on the thread, somewhat like the crystals of sugar-candy on string. When it is undesirable to remove even a few drachms of blood, we may examine the fluid effused by the application of a blister, since the uric-acid thread experiment may be as readily employed for the discovery of uric acid in blisterserum as in blood-serum. It is only necessary to observe the precautions alluded to in examining the blood-serum, and also to be careful not to apply the blister to an inflamed part, since the existence of inflammation appears to have the power of preventing the appearance of uric acid in the effused serum.' SECTION 2. THE EXPECTORATION. The character of the expectoration often furnishes us with instructive signs. The basis of all kinds of expectoration is the natural secretion of the mucous membrane of the airtubes, which is a transparent, colorless, glutinous liquid, consisting chiefly of water, mucus, and saline matter. In simple catarrh the natural secretion is merely increased in quantity; in bronchitis the sputa are often glairy-like white of eggand streaked with blood; in hæmoptysis the expectoration may consist entirely of blood; in phthisis, purulent fluid and portions of softened tubercle are expectorated, occasionally with cretaceous or calcareous masses of phosphate and carbonate of lime; while in pneumonia, at the outset, there is merely expectoration of bronchial mucus, but in two or three days the sputa assume a very characteristic appearance, being transparent, tawny or rust-colored, and united into a jelly-like mass of great viscidity. To examine the sputa microscopically, they should be thrown into water, when the lighter portions will float on the surface, while the more dense sink. These latter can be broken up, and small particles placed on a glass slide for examination. The matters usually found consist of epithelium, portions of food-as muscular fibre, oil-globules, starch granules, &c.— 'Medico Chirurgical Transactions, vol. xxxvii, p. 51. and occasionally of vegetable fungi, which are often present about the fauces. In phthisis, a number of small, round, oval, or triangular-shaped bodies-tubercle corpuscles—are frequently found, containing granules in their interior, and mingled with granular matter. Occasionally fine molecular fibres, which have been separated from the areolar and elastic tissue of the air-cells of the lung, are also seen, showing that ulceration or sloughing of the pulmonary texture is going on. Schroeder van der Kolk states that these fragments may be found before the physical signs of ulceration of the lungs are well marked; but Dr. Hughes Bennett-a great authority on this subject-disputes the assertion, though he allows that in doubtful cases, especially where-from chronic pleurisy or pneumonia-there is dulness on percussion, whilst the other physical signs are more or less obscure, the presence of these fragments will confirm a previous suspicion of existing phthisis. In pneumonia, fibrinous casts of the minute bronchi may often be observed, sometimes infiltrated with pus-corpuscles. And, lastly, the dirty green or black inspissated sputum, so commonly expectorated in the morning by residents in cities, consists of mucus and epithelial cells containing carbon, probably derived from the smoky atmosphere. SECTION 3. VOMITED MATTERS. But little attention has been paid to the microscopic examination of these matters, and but little therefore is known of them. The chief substances found are epithelium, starchgranules, torulæ and other varieties of vegetable fungi―resembling the yeast plant, vibriones, and sarcina. The Sarcina Ventriculi-first described by Goodsir-consist of square bundles, divided by vertical and horizontal lines into four parts, and each having a resemblance to a woolpack -whence its name; they are seen either singly or aggregated into masses. These vegetable parasites are found in the vomit when it is very acid, and when it resembles yeast in ap pearance. Dr. Todd has found the sarcina in ulceration and enlargement of the stomach with contraction of the pylorus, and he suggests that these vegetable organisms result from the long detention of food in the stomach. There is but little doubt that this explanation is correct; but it is also probable that the intensely acid fluid in which the sarcinæ are found may itself irritate and close the pylorus spasmodically; in such cases consequently, if we check the formation of these growths we shall cure the disease. 1 Op. cit. p. 92. Sarcinæ have also been found in the urine, fæces, and in the fluid of the ventricles of the brain. SECTION 4. THE URINE. Healthy human urine is a limpid, pale, amber-colored fluid, free from any deposit, of acid reaction, unaffected by heat, nitric acid, liquor potassæ, &c., and having an average specific gravity of 1018. Dr. Prout estimates the normal quantity of urine secreted in the twenty-four hours to be from thirty ounces in the summer, to forty in the winter. A distinction is usually drawn between the urina potus, or that passed shortly after taking fluids; the urina chyli, or that evacuated soon after the digestion of a full meal; and the urina sanguinis, or that which is voided on first awaking in the morning, and which may generally be taken as a fair specimen of the renal secretion. The solid matters in the urine may be said to consist of urea, uric acid, hippuric acid, vesical mucus and epithelium, ammoniacal salts, fixed alkaline salts, earthy salts, and animal extractive. Solid Contents.-To estimate the solid contents as well as the weight of an ounce of urine, of any specific gravity between 1010 and 1040, the late Dr. Golding Bird constructed the following very useful table: 1022 447.1 22.918 1037 453.6 39.104 40.206 1024 448. 25.051 1039 454.5 41.300 REACTION OF THE URINE TO TEST PAPERS. 233 Clinical Examination of Urine.-On making a clinical examination of the urine, we should first ascertain the quantity passed in the twenty-four hours; its acidity or alkalinity, by the use of litmus and turmeric papers; its specific gravity, by means of the urinometer; and its behavior on the application of heat, nitric acid, and liquor potassæ. To examine it microscopically, a portion should be placed in a conical glass, and allowed to stand for some hours; a few drops of the deposit at the bottom of the glass are then to be placed by means of a pipette on a glass slide, and covered with thin glass. Crystals of uric acid, deposits of urate of soda, and deposits of phosphates, will be readily distinguished with a good half-inch achromatic object-glass; oxalate of lime, carbonate of lime, cystine, blood-corpuscles, casts of tubes, pus, mucus, epithelium, and certain fungi, as torulæ, &c., will require a quarter-inch object-glass; while spermatozoa and vibriones can only be distinctly examined with the one-eighth of an inch glass. An Increased Flow of Urine, or diuresis, may be temporary, and merely dependent on the large quantities of fluid taken; or it may be permanent for a time and associated with disease, as it very constantly is in diabetes, and in those states of the system connected with a peculiar state of nervous irritability as hysteria, &c. A Deficiency of Urine may also be the temporary result of abstinence from fluids, unusual cutaneous activity, &c.; or it may be permanently associated with certain constitutional and local affections, as with inflammatory states of the system generally. Reaction of the Urine to Litmus and Turmeric Testpapers. In many diseases-as gout, rheumatic fever, &c.— we find the urine unusually acid, which may be owing to an excess of acid, or it may be caused by the presence of oxalic acid. On the other hand, this secretion may be alkaline, though it is very doubtful if the urine is ever so secreted. It generally happens thus:-a patient is unable completely to empty his bladder, and therefore, after each attempt to do so, a small quantity of urine is left which soon becomes alkaline; this suffices to contaminate the acid urine as it drops guttatim from the ureters. Of course, as a rule, the vital endowments of the bladder are sufficient to preserve its contents from undergoing that change which so readily takes place out of the body, viz., decomposition. But this preservative power depends upon the integrity of the spinal nerves and branches from the organic system supplying this viscus; if, therefore, |