chlorid. An amethyst-blue solution results. If now to this solution a portion of the gastric contents be added containing lactic acid, the blue color will be discharged, to be replaced by a faint lemonyellow.

If, also, the filtrate from the stomach contents be added to a dilute solution of ferric chlorid, and lactic acid be present, the faint-yellow color will give place to a much deeper tint.

In both these tests it is better to shake a few cubic centimeters of the gastric filtrate with a few cubic centimeters of ether in a test-tube, and after evaporating the solution of lactic acid in ether, by allowing the ether to stand in a watch-glass, to dissolve the residue in a little water, and to use the solution so obtained for the Uffelmann and ferric chlorid tests.

Butyric Acid.-This acid is often present in the gastric contents in cases of marked dilatation of the stomach. It may be recognized in the ethereal extract by the characteristic odor of rancid butter.

The Digestive Ferments.-There are, unfortunately, no quantitative tests that may be easily carried out, by which the amount of pepsin, and therefore the digestive power of the gastric contents, may be quantitatively estimated. One can simply examine the fluid to see if the digestive power is still present. In order to do this, some compound whose change in digesting may be readily observed is taken. For this purpose either coagulated eggalbumin or fibrin may be used. The latter acts more satisfactorily, but the former is more conven

ient for ordinary clinical work. With fibrin the digestion proceeds at room-temperature, while eggalbumin requires the temperature of the bodyabout 37°-39° C.-for digestion. The fibrin used should be derived from ox-blood. A small bit of the washed fibrin should be placed in a test-tube and covered with the gastric juice. If digestion takes place, the fibrin swells up and finally disappears.

If egg-albumin be used, the uncoagulated white of egg is drawn up into small tubes made by drawing out ordinary quill tubing in the flame, and coagulating the albumin by passing the capillary tube containing it through the flame till the contents are white. This may be placed in a tube containing gastric juice and the whole placed in an incubator at 40° C. Another method consists in coagulating the albumin in the shell and cutting out cylinders, about 5 mm. in diameter, with a cork-border, or glass tube. These cylinders are cut thin in the form of circular slices, and are then placed in testtubes containing the gastric juice.

Examination of the Vomit.-It may be necessary in some cases of suspected poisoning to examine the vomit. The same procedure for the clinical examination will be applicable as in dealing with a test-meal. It will be found that the fluid will be even more complex than that obtained where only bread and water have been given. The vomitus will contain larger amounts of organized matter, the result of the breaking down of food. Among the substances which will be encountered in the microscopic examination will be

muscle-fibers, crystals or globules of fat or of fatty acids, elastic fibers, connective tissue, starchgranules, and vegetable cells.

Diagnosis of Gastric Disease.-Acute Gastritis.—In this disease, which may or may not follow mechanical or chemical irritation of the stomach, the clinical features are well marked. Hydrochloric and lactic acids are often lacking at the outset, and the digestive power of the gastric juice will be found to be below normal. Bilepigment and the biliary salts will be sometimes found in the vomit, and will be recognized by the appropriate tests.

Chronic Gastritis.-The vomit in this disease is thin, and in cases associated with dilatation of the stomach will be excessively so. Hydrochloric acid will usually be found to be present, although in rare cases the contents of the stomach have been alkaline in reaction.

Simple Gastritis.-In simple gastritis the testbreakfast is not followed by increased acidity, and the proportion of hydrochloric acid is usually below normal. The pepsin is also proportionally decreased. In acid gastritis the hydrochloric acid is above normal, and may be increased over 100 per

cent.

In mucous catarrh of the stomach the amount of acid falls very considerably, and in a large percentage of cases is entirely absent.

In atrophic gastritis the contents of the stomach are free from hydrochloric acid, pepsin, and the milk-curdling ferment.

Chronic Ulcer of the Stomach.-In this disease the clinical features which are of importance are the excess of hydrochloric acid and the presence of blood. The hyperacidity of the gastric juice is usually very marked in gastric ulcer, and may range from 0.4 to 0.6 per cent. As the disease progresses the hyperacidity diminishes. The blood may be in clots, or from contact with the hyperacid contents of the stomach may be changed to dark-brown, coffee-colored masses which consist chiefly of acid hematin.

Gastric Carcinoma.-The examination of the contents of the stomach in this most important disease may reveal more or less characteristic features. Hydrochloric acid may be said to be practically always absent. Cases in which it is found are rare. Sarcinæ ventriculi are often present in large numbers. Lactic acid may replace the hydrochloric acid, and hence may be found in relatively large quantity.

Gastric Dilatation.-The stomach contents in this disease show the general characters of enfeeblement of digestive power, and the loss of activity of the stomach-wall. The contents are, as a rule, dilute, and contain the remains of undigested food. The signs of long-continued fermentation are well marked. Yeast-cells and sarcina will be seen, and the amount of hydrochloric acid will vary within wide limits.

TABLES FOR URINARY DIAGNOSIS.

The following is a list of the diseases of the urogenital tract (those which are distinguishable through the urine are so marked); also a list of systemic diseases and special conditions causing definite changes in the urine.

The characteristic diagnostic signs in the urine, when present, are given. The list of diseases is complete, and therefore includes many pathological conditions which yield no characteristic signs in the urine. These are so designated. By consulting such a list the diagnostician may either from definite signs or by exclusion often arrive at a diagnosis.

While certain deviations from the normal occur in the urine under pathological conditions, and while these deviations are definite indices of such pathological condition, yet there are many deviations from the normal, the interpretation of which is quite obscure, and many pathological conditions, even of the urogenital tract, which yield no clue by the urine; moreover, several pathological conditions give the same urinary conditions, and are therefore indistinguishable from one another through this means. We must, therefore, as in all chemical and microscopical clinical investigations, consider our chemical and microscopical and physical examinations complementary one to the other.

I. DISEASES OF THE UROGENITAL TRACT. 1. Malformations of the external genitalia (no urinary changes).

2. Affections of the external geni

talia.

Herpes and abrasions.

Chancre and chancroid.

Growths, benign and malignant.

(No urinary

changes.)