THRUSH.

Thrush is a local disease, preferably attacking mucous membranes lined with pavement epithelium, and resulting from the lodgment and proliferation of the thrush-fungus. The lodgment of the fungus leads to the formation of milky-white deposits varying from the size of a millet-seed. to that of a lentil. These gradually undergo enlargement toward the periphery, and in the absence of therapeutic intervention coalesce finally into large membranes.

Microscopic Examination of Thrush-deposits.—Microscopic examination of the white points that represent the first stage of the thrush-eruption discloses, in addition. to squamous epithelium, molds and bacteria of various kinds, always in large number, the two phases of the thrush-fungus (vidium albicans): the mycelial threads and the conidia. The former are threads of double contour and of varying thickness and length, with transverse septa and indentations, from which often lateral branches of equal or less thickness pass off. The conidia, which grow from the mycelia, at their extremities or in the neighborhood of the septa, are more or less spherical, separate readily from the mycelia, and lie among them, at times isolated, at times in groups.

Occurrence of Thrush.-Thrush occurs most commonly in new-born children, principally about the second week of life. In older children and in adults thrush occurs only when protracted disease (typhoid fever, tuberculosis, etc.) has induced general enfeeblement of the organism. In the new-born, however, an eruption of thrush by no means presupposes a particular impairment of the general health. The mucous membrane of the infant is obviously quite especially predisposed to the vegetation of the thrush-fungus. In experimental transmission of thrush the disease will develop upon the healthy mucous membrane of wellnourished children.

The preferable seat of thrush is the mucous membrane of the mouth, and here the tongue, the inner surface of the lips and of the cheeks, are most commonly invaded. Next in frequency deposits of thrush appear upon the gums, in the pharynx, and also in the upper portion of the esophagus, on the anterior and upper surface of the epiglottis, and exceptionally upon the true vocal bands. In all of these

situations pavement epithelium is present, and it has been assumed that the thrush-fungus is capable of proliferating only upon mucous membrane covered with such epithelium. The thrush-fungus is not rarely encountered in the vagina of pregnant women, which likewise is lined with pavement epithelium. It occurs, however, also upon mucous membranes lined with other kinds of epithelium-as, for instance, that of the stomach, the posterior surface of the epiglottis, the deeper portions of the respiratory tract, although but seldom in all of these situations. The thrush-fungus has been demonstrated repeatedly in bronchopneumonic foci, and in numerous instances upon the mammary glands and mammillary areola of nursing women whose children suffered from thrush, and in one instance in encephalitic suppurative foci in a child suffering from thrush.

Course of Thrush.-The thrush-fungus penetrates the uninjured epithelial surface, and develops beneath the uppermost layer of epithelium, within the deeper portions of the mucosa. Only rarely does it invade the submucosa. The abundant fungous vegetation raises the upper epithelial layer, and gradually separates it from the connection with the lower layers necessary for its nutrition, so that it undergoes necrosis and exfoliation. The thrush-membrane is then exposed to view. The thrush-proliferation usually gives rise to mild local-irritative manifestations. The mucous membrane generally appears somewhat altered at the site of the thrush-deposits. It is dark red, slightly swollen, dry, and distinctly sensitive to touch. The signs of an actual inflammation are, however, not discoverable microscopically. It has been assumed that the thrush-fungus can find lodgment only upon mucous membranes the seat of catarrhal inflammation. This, however, does not appear to be correct, but the slight evidences of irritation may really be the result of the purely mechanical action of the fungous vegetation. The saliva of patients suffering from thrush invariably has an acid reaction. There is no suggestion of chemic activity on the part of the thrush-fungus, of any production of toxin. There is an absence of fever and, in fact, of all constitutional manifestations. The symptoms are of a purely local nature. The fungous proliferation may become dangerous only when, by reason of especially luxurious development, it obstructs the esophagus or the larynx; and, further, in small children,

through impairment of the nutrition, the tenderness of the mouth interfering with nursing. In general, however, the disease is a thoroughly benign one. The thrush-vegetations have no especial tendency to extend, and only exceptionally have extension of the thrush-fungus into the interior of blood-vessels and transmission through emboli been observed. The vegetations can be readily removed by rubbing the thrush-plaques with soft cloths dipped in a solution of borax (sodium biborate 2.0, glycerin 4.0, distilled water 34.0).

Sources of Infection for Thrush.-The thrush-fungus is present in the air of dwelling-rooms, in the feces of infants, upon rubber nipples, upon saccharine and amylaceous articles of food, etc., and it may gain entrance into the mouth with all of these. Frequently, as has already been mentioned, the thrush-fungus is found in vaginal mucus, and thrush in the infant has been attributed to conveyance of the fungus from the maternal genital canal during the act of parturition. This is, however, certainly not the ordinary mode of infection, as the period of incubation of thrush, as determined by numerous inoculation-experiments, is only four or five days, and the disease usually does not appear in infants before the second week.

Culture and Botanic Position of the Thrush-fungus. In accordance with the appearance of the thrush-fungus in the thrush-membrane described, the fungus bears a close resemblance to the varieties of oidia that cause the dermatomycoses, and it has, therefore, been given the name oidium albicans. Grawitz, then, demonstrated subsequently by culture that the thrush-fungus is not a mold, but rather a budding fungus. As numerous later investigations have shown, the thrush-fungus grows upon culture-media of acid reaction and containing an abundance of sugar (prunedecoction agar) in filaments of actively budding yeast-cells. If these be transferred to ordinary meat-peptone agar-thus to an alkaline nutrient medium, deficient in sugar-distinct threads develop in addition to the budding cells. Retransferred to an acid medium, the threads again develop almost exclusively into yeast-conidia. The oidium albicans is thus a budding fungus that, under certain nutritive conditions, forms hyphae. Other observers, however, maintain that the thrush-fungus is a mold. The organism does not liquefy gelatin. Upon gelatin-plates whitish colonies form,

and in stab-cultures whitish-yellow granules that send radiating processes into the nutritive medium. Upon agar a whitish-yellow, wrinkled deposit forms; upon potatoes a dense, white coating, and upon bread-pap a thin, white deposit. The temperature-optimum is 37° C. (98.6° F.).

It has been demonstrated experimentally that the thrushfungus is the actual cause of thrush. It has been possible to develop thrush upon healthy mucous membranes both by means of the bands of buds, and with the filamentous cells. Rabbits die in from twenty-four to forty-eight hours after intravenous injection of emulsions of the thrushfungus, a general mycosis resulting, and networks of thrush-vegetations being found in the kidneys, the liver, etc. (G. Klemperer). This pathogenic action of the thrushfungus is, however, not constant.

The diagnosis of thrush is made by microscopic examination of the thrush-deposit; cultivation of the fungus is not necessary.

ACTINOMYCOSIS.

The actinomycosis of animals was recognized as a distinct disease in 1877 by Bollinger, and in its lesions peculiar vegetable structures (actinomyces, ray-fungus) were invariably found.

Actinomycosis is a disease peculiar to cattle, having been but seldom observed in other animals (swine, dogs). The usual seat of the disease in cattle is the lower jaw, less commonly the upper jaw, or also the adjacent soft parts, especially the tongue. The disease of the jaws leads to the formation of tumors of greater or less extent, which subsequently rupture outward through the skin, less commonly into the mouth, and thus come into view as ulcerated nodules. On section the tumor appears pale yellow; it is in general soft, but presents, in places, especially softened, yellowish areas of varying size, from which on scraping with the knife a substance resembling pus and numerous yellowish granules as large as grains of sand are obtained. Examined microscopically the tumor-mass represents granulationtissue; the yellow coloration is dependent upon abundant fatty degeneration of the cellular elements. The essential feature and the peculiar characteristic of the actinomycotic nature of the newformation consist in the yellow granules present, the so-called actinomyces-granules, to whose structure reference will be made These are fungous formations, and represent the cause

later.

of the disease, as has been established with certainty by the successful transmission to calves of actinomycosis by means of such granules (Ponfick and others).

The disease in animals presents, in the first place, the characters of an inflammatory new-formation, which develops around the fungous proliferation as a foreign body; besides, there is considerable destructive tendency--the proliferating fungi in their growth displacing and destroying all opposing tissues.

Infection in animals probably takes place principally through the mouth in feeding. The ray-fungus is said to be present in feed, in wheat-grains, which play an important part in the process of infection. Infection through the superficial integument, through the lungs, etc., is possible also, but occurs less commonly, A case of actinomycosis of the udder has been observed in a pig, and another of miliary pulmonary actinomycosis in a cow.

Actinomycosis in Human Beings.-Isolated cases of actinomycosis in human beings had already been observed by B. v. Langenbeck (1845) and by Lebert (1857), but the disease was first clearly recognized and accurately described as an independent affection by J. Israel in 1878. Actinomycosis in human beings differs from the same disease in cattle in its slighter tendency to tumor-formation, and its marked tendency to insidious, widespread extension, which may finally lead to involvement of all of the viscera. The chronic inflammation that takes place around the fungous deposit is identical with that which occurs in animals. The newly formed granulation-tissue undergoes fatty degeneration more quickly, however, with disintegration or suppuration, while the fungous proliferation progresses and gives rise to fistulous formation, undermining the skin, penetrat