violet color is reached. From the amount of soda solution used may be computed the acidity due to all acid principles except loosely combined HCl.

To the third beaker, one to two drops of phenolphthalein solution are added and it is titrated as before. The final reaction is indicated when the rose color first appearing no longer darkens on further addition of soda solution. From the amount of soda solution used the total acidity is computed.

Significance of Changes in the Amount of HCl in Stomach.-If the normal amount is found (.1 per cent to .2 per cent), it is strong evidence against any organic disease of the stomach. The symptoms referred to the stomach when a normal amount of HCl is present must be due either to a nervous or atonic condition. Continuous hyperacidity (over .2 per cent) occurs most frequently in neurotic dyspepsia, is very often present in simple ulcer, and may often be a symptom of the early stages of a chronic gastritis. It speaks strongly against carcinoma except when a simple ulcer is undergoing carcinomatous transformation. Continuous subacidity (under .1 per cent) is seen in chronic gastritis, especially with dilatation and atony, in some cases of simple ulcer with chronic gastritis, and in incipient carcinoma. Anacidity is a frequent and persistent symptom of the later stages of chronic gastritis, when pepsin is also lacking. When pepsin is present, it may indicate a neurosis. When other signs are favorable, it speaks strongly for carcinoma. If the amount of acidity due to HCl varies markedly, in all probability it indicates a neurosis.

Lactic Acid.--The test for lactic acid usually employed is Uffelmann's. Although there are sources of error, this test is fairly reliable. Test: Take 10 c.c. of a 5 per cent solution of carbolic acid; add 20 c.c. of distilled water, and one drop of a 5 per cent solution of ferric chloride. An amethyst blue color appears, which may soon change, making it imperative to use the solution when fresh. A few drops of the stomach contents added to this solution produces a lemon color if lactic acid be present.

Significance of Lactic Acid.—It is often ingested with food, and forms early in digestion when milk or bread have been taken. It is seldom present after eating carbohydrates. It is found in traces only during the course of non-malignant disease of stomach. It is usually present in larger proportion in dilatation with stagnation of the gastric contents. If it is associated with retention and absence of HCl it is strongly suggestive of carcinoma.

Pepsin.-Marked diminution or absence indicates a corresponding disturbance of the glandular activity. It may exist, however, with a variety of lesions.

Absorption and Motility.-The absorption activity of the stomach may be roughly indicated by Penzoldt's test: When 5 grammes of potassium iodide are taken in a gelatine capsule, iodine appears in the urine and saliva of the normal subject within six to fifteen minutes, while with deficient absorptive capacity its appearance is much later. The iodine may be detected by applying a few drops of saliva or urine with one drop of strong nitric acid to starch paper, which, in the presence of iodine, turns blue or violet.

Sahli's test of gastric efficiency consists in the use of a pill containing a small amount of either iodoform or methylene blue, which is enveloped in a small bit of the rubber dam used by dentists, the neck of the little. bag formed being tied off with the finest obtainable raw catgut. Such a

pill is given at the end of the ordinary noon meal and the urine passed at stated intervals during the afternoon and evening is either examined in regard to the first appearance of a greenish color if methylene blue was used, or is tested for the presence of iodoform in case this indicator was chosen. The latter substance has the practical advantage that it may be detected with equal certainty in the saliva. The appearance of either substance in the urine, or of iodoform in the saliva, indicates satisfactory gastric digestion and a negative result the reverse, the information obtained being, according to the author, a sufficient index as to the combined activity of the hydrochloric acid and the pepsin.

The motility of the stomach is best determined by giving a test meal. at night on an empty stomach, and examining the washings the next morning. Normally no traces of ingested food should remain.

A chemical examination of the gastric contents simply shows us the chemical composition of the gastric secretion at the time the analysis was made, and is simply one factor in the diagnosis, prognosis, and therapeutics of digestive disturbances of whatever nature.

SPUTUM

GROSS CHARACTERISTICS

Types of Sputum.-The following special types should be noted: Mucoid. A good example of this is seen in chronic bronchitis. It is light in color, slightly translucent, viscid, tenacious, elastic, and very slightly aerated.

Mucopurulent. Seen in acute bronchitis. The admixture of pus with mucoid sputum renders it yellow, opaque, less tenacious and elastic. It is more completely aerated.

Purulent. In severe bronchitis, tuberculosis, and with rupture of lung abscess it may be pure pus. Purulent sputum has more pus than mucus and no viscid quality.

Blood-Stained.-This is seen in acute bronchitis, pneumonia, tuberculosis, tumors of the lung and hæmophilia. The blood exceeds the mucus. The viscidity is reduced, although the sputa remains coherent.

Pure blood is expectorated in penumonia, phthisis, ruptured arteries, aneurysms, asphyxia, various septic conditions of infants, hæmophilia, trauma, and some blood diseases.

Rusty sputum is peculiar to lobar penumonia. It consists of gelatinous pellets of mucus slightly mixed with pus and uniformly tinged a rusty color. This type has been noticed after an attack of acute pulmonary edema.

Serous. This is semifluid. Upon standing, it separates into two layers. Such mixtures are common in the terminal stages of bronchitis, in Bright's disease, tuberculosis, pneumonia, and endocarditis.

Pure serum may be expectorated in acute cedema of the lungs, occurring in the initial stages of pneumonia or in nephritis with arterio-sclerosis.

Fibrinous coagula are often mixed with the sputa in chronic bronchitis and pneumonia. Fibrinous casts of the bronchi may be expectorated in a type of chronic bronchitis.

Gangrenous sputum is characteristic of putrefaction and necrosis of lung tissue. Prune-juice expectoration, indicating a decomposition of blood, is common in pneumonia. Gangrene of the lung gives a most fetid discharge, which, upon standing, usually separates into three layers: the uppermost being frothy mucus and pus; the middle, serum; while the heavier, at the bottom, is solid portions of tissue.

Nummular sputum is the name given to purulent, coin-shaped sputa coming from old cavities with suppurating walls. Bile pigment may stain sputa in some of the severe forms of infectious disease and jaundice. Actinomyceces in colonies appear as small, white, partly calcified granules and resisting considerable pressure. Curschmann's spirals can usually be detected by the naked eye, as whitish, opaque, spiral, threads, 1 to 10 mm. in length. Masses of lung tissue are small, grayish in color, and irregular in outline. Hamatoidin is seen as dark brown particles resisting much pressure.

MICROSCOPICAL EXAMINATIONS

Mucus and fibrin appear in smear preparations as fine or coarse reticulated threads. Red blood-cells have their ordinary appearance. Epithelial cells from the mouth are squamous; from the bronchi or nares columnar with or without cilia; from the lung parenchyma they are rounded, large, and usually contain black pigment. In pulmonary congestion from endocarditis, the epithelium contains large brownish grains of blood pigment. Leucocytes are recognized by their multiple nuclei and clear bodies.

Elastic fibres, occurring singly or in masses showing a distinct alveolar arrangement, are recognized as large, wavy, highly refractive threads lacking the double contour of vegetable fibre. They can be said to indicate destruction of living tissue only when they appear in characteristic alveolar arrangement, and are most frequent in tuberculosis. They have also been found in bronchiectases, abscesses, and rarely in pneumonia. CharcotLeyden crystals, elongated and diamond shaped, are found in chronic bronchitis. Hæmatoidin, fatty acid, cholesterin, calcium carbonate, and triple phosphate crystals are also occasionally found. Curschmann's spirals, found in chronic bronchitis and asthma, frequently contain a number of Charcot-Leyden crystals within the meshes.

Microorganisms.-Molds, aspergillus, leptothrix, and yeast fungi are sometimes seen in sputum from phthisis cavities and abscess of the lung. The ray fungus is observed in pulmonary actinomycosis. It appears as branching, interwoven threads, having swollen or club shaped ends, and can be easily demonstrated. Streptococci are frequently found in the mouth, and may have no pathological significance. In severe acute bronchitis they have been found in large numbers. With staphylococci, they are abundant in sputum from cavities.

Pneumococci (Diplococcus lanceolatus) may often be found in the mouths of healthy individuals, but are especially abundant in the expectoration of pneumonia. The pneumobacillus of Friedlander is found in a few cases of pneumonia. It is encapsulated and resembles somewhat the pneumococcus except that it is rod shaped, broader, longer, and has rounded ends. Both may be stained by Welch's method as follows, but the latter decolorizes by

TRANSUDATES, PUNCTURE FLUIDS, CYST CONTENTS

37

Gram's method. Welch's Method.-The sputum is smeared, dried, and fixed on a glass slide by passing through a flame until the slide is as hot as the hand can bear. Then flood with glacial acetic acid, which is immediately drained off. Flood two or three times with aniline water gentian violet solution. Wash in a 2 per cent aqueous solution of sodium chloride, in which it may be mounted. It must not be washed with water. To prepare aniline water gentian violet, which must be used only when fresh, shake nine parts of distilled water with one of aniline oil, and filter through filter paper. To the filtrate add one tenth as much of saturated alcoholic solution of gentian violet.

Bacillus of influenza is a minute straight rod, with rounded ends, often staining more deeply at the ends. This often gives it the appearance of diplococcus. It is found in immense numbers, singly or in clumps of one hundred or more and often within the bodies of leucocytes. They are best demonstrated by staining five minutes with a weak solution of carbol fuchsin.

Tubercle bacillus can be found in the vast majority of cases of pulmonary tuberculosis. This bacillus grows in slender, straight, or slightly curved rods. The younger germs stain uniformly with carbol fuchsin, while the older present unstained points resembling vacuoles or spores, and sometimes present the appearance of a chain of cocci. They may occur singly, or two or more may lie side by side or end to end. Method of staining.-Fix the thinly spread sputum upon a glass slide by means of heat. Flood with carbol fuchsin for two minutes, gently heating. Wash thoroughly in water, and decolorize by flooding the specimen with acid alcohol solution for one minute. Wash in water, and counter-stain with aqueous methylene blue. solution for about one minute. Wash in water, dry in air, and mount in balsam. The bacillus appears bright red, and the other parts of specimen are blue.

Micrococcus tetragenes occurs in groups of four and are very frequently found in tuberculosis, associated with the tubercle bacilli. When found with the latter they are said by Hoch to be an indication of cavity formation. They stain readily with all of the aniline dyes, particularly methylene blue.

The smegma bacillus stains with almost as great a tenacity as the tubercle bacillus, and to distinguish it from the tubercle bacillus the specimen must be decolorized in alcohol for about eight to twelve hours, after which time the smegma bacillus is decolorized.

TRANSUDATES, PUNCTURE FLUIDS, CYST CONTENTS

Aids to Differentiation.-Collections of serous fluid in body cavities or tissue spaces as the result of mechanical disturbance of the circulation, changes in the blood or in the walls of the vessels, unaccompanied by inflammatory phenomena, are true transudates.

The careful chemical and microscopical examination of the fluid is an aid to differentiation between an exudate and a transudate. The specific gravity in transudates is usually lower than 1.015, while in exudates it is higher than 1.018. The albumin content in transudates is less than in exudates. In the former it averages between 1 per cent and 2.5 per cent and in the latter 4 per cent to 6 per cent. As exudates are inflammatory in origin, we expect

to find the products of inflammation, pus, epithelial cells, microorganisms, etc., while in transudates these elements are not usually present and occur only after long standing and introduction of infectious elements from without. Cyst contents may show the echinococcus hooklets, which are diagnostic.

EXUDATES

Exudates are inflammatory in origin, and their examination can aid as to the cause of inflammation. They may be serous, bloody (hæmorrhagic), fibrinous (serofibrinous), purulent (seropurulent), or chylous. Chyloid exudates differ from the chylous in that they contain much less free fat. The turbidity is due rather to cellular débris and lecithin. They may coagulate in the cavity or after aspiration. Microscopical examination is most important for the detection of isolated cells, or larger particles of a tumor, or of tubercle bacilli, gonococci, or other pyogenic microorganisms. Tuberculous exudates are usually scrous or hæmorrhagic, the latter form indicating more severe inflammation. A hæmorrhagic pleuritic exudate is usually tuberculous, and pleuritic exudates are more usually bloody than those of the peritonæum. Bacilli are present in tuberculous exudates in very small numbers, but in the necrotic foci they are more abundant. Rarely they may be found by staining the sediment. The best test, however, is inoculation into the peritoneal cavity of a guinea-pig.

Carcinoma or endothelioma of serous membranes is frequently accompanied by an exudate, which is usually serous, but often bloody. Isolated cells, or small masses of tumor, may be found in the sediment; but the cells must show the mitotic changes under the microscope to give a positive diagnosis. The diagnosis can frequently be made upon this basis of the presence of atypical epithelial cells alone.

Joint fluids usually contain mucus and are viscid. The exudate of traumatic or rheumatic synovitis is usually clear and sterile; while in tuberculous synovitis the fluid may be bloody or seropurulent, and tubercle bacilli may be demonstrated. In gonorrhoeal synovitis fluid is serous or seropurulent and the gonococcus may often be demonstrated.

Discharges. The gonococcus occurs principally in genitourinary discharges, but may be found in gonorrhoeal infections of the rectum, mouth, eyes, serous cavities, and also in the blood. The usual location, however, is in the genitourinary tract, where it grows on surfaces lined by columnar epithelium. In the male, the gonorrhoeal germ is found in acute and chronic urethral discharges. In gonorrhoeal cystitis it is found in the threads, socalled "gonorrhoeal shreds." In the female it is most abundant in and often limited to the urethral pus. Next in frequency it is found in the discharges from the cervix uteri. In the vaginal discharge other diplococci are often present, which makes differential diagnosis difficult. Hence it is always better to take the pus from the urethra or cervix. In female children the gonococcus is often found in the vaginal discharge, but seldom in the urethra. Children do not usually have gonorrhoeal cystitis.

In looking for the gonococcus, we must note the following characters: It must be a biscuit shaped diplococcus. It must be found within bodies of pus cells. It must be decolorized by Gram's method.