ated central part of the colony peculiar zooglea are formed, having a sausage or screw shape, or wound in spirals like a corkscrew. The younger colonies, which have not yet reached the surface of the gelatin, are more compact, rounded or nodular, later covered with hair-like projections, and becoming radiated like the superficial colonies. If the culture-medium be concentrated, or the culture has been frequently transplanted, the phenomenon is less marked and may not occur. Bouillon. In this medium the organism grows rapidly, and quickly clouds the fluid. A pellicle soon forms upon the surface and a mucilaginous sediment occurs later. Gelatin Punctures.-Puncture cultures in gelatin are not characteristic. A stocking-like liquefaction of the gelatin extends so rapidly that the entire gelatin is liquefied in a few days. Anaërobic cultures do not liquefy. Agar-agar. Upon agar-agar the bacillus forms a moist, thin, transparent, rapidly extending layer which rarely reaches the sides of the tube. Upon agar-agar plates ameboid movement of the colonies may also occur. Potato. Upon potato the growth occurs in the form of a smeary patch of soiled appearance. Milk is coagulated. Metabolic Products.-The bacillus usually produces alkalies. Indol and phenol are formed from the peptone of the culture-media. Nitrates are reduced to nitrites, and then partly reduced to ammonia. In most culture-media not containing sugar the bacillus produces a very disagreeable odor. In culture-media containing either grape- or cane-sugar fermentation occurs both in the presence and in the absence of oxygen. Milk-sugar is not decomposed. Pathogenesis. It is a question whether or not Bacillus proteus is to be ranked among the pathogenic bacteria. Small doses are harmless for the laboratory animals; large doses produce abscesses. A toxic substance resulting from the metabolism of the organism seems to be the cause of death when considerable quantities of a culture are injected into the peritoneal cavity or blood-vessels. The bacilli do not seem able to multiply in the healthy animal body, but can do so when previous disease or injury of its tissues has taken place. The proteus has been secured in cultures from wound and puerperal infections, purulent peritonitis, endometritis, and pleurisy. When the local lesion is limited, as in endometritis, the danger of toxemia is slight; but when widespread, as the peritoneum, it may prove serious. Bacillus proteus has also been found in acute infectious jaundice and in acute febrile icterus, or Weil's disease. Bordoni-Uffredizzi has shown that the proteus quite regularly invades the tissues after death, though it appears unable to maintain an independent existence in the tissues during life, and is probably of importance only when present in association with other bacteria. It at times grows abundantly in the urine, and may produce primary inflammation of the bladder. The inflammatory process may also extend from the bladder to the kidney, and so prove quite serious. Epidemics of meat-poisoning have been thought to depend upon Bacillus proteus. One of them was studied by Wesenberg,* who cultivated the organism from the putrid meat by which 63 persons were made ill. Silverschmidt† and Pfuhl‡ have made similar investigations with similar results. AMEBÆ AND SUPPURATION. The process of suppuration is not confined to bacterial micro-organisms, but is shared to a limited extent by the protozoa. Thus, Entamoeba histolytica (q. v.) is, to all appearances, the sole excitant of the abscesses of the liver secondary to dysentery. It is true that these are cold abscesses and necrotic rather than distinctly purulent in character, yet it seems best to speak of the organism in this connection. Entamoeba buccalis (Prowazek§) is a small ameba that has been found in purulent exudates in the oral tissues of persons with carious teeth. Amoeba kartulisi (Doflein) appears to be capable of exciting suppuration. It was found by Kartulis in the pus from an abscess of the right side of the lower jaw. The patient was a man aged forty-three years who had been * "Zeitschrift für Hygiene," etc., 1898, xxvIII. † Ibid., 1899, XXX. Ibid., 1900, xxxv. § "Arbeiten a. d. Kaiserl. Gesundh.-Amt.," XXI, 1, Bull. 1904, p. 42. "Die Protozoa als Krankheitserreger," Jena., 1901, p. 30. * operated upon for the removal of a piece of bone. It is 30. to 38 u in diameter, is actively motile. Its coarse protoplasm contains red and white blood-corpuscles. Kartulis found the same organism five times in other cases, and Flexner † found it also. Amoeba mortinatalium, described by Smith and Weidman,‡ was found in distributed small purulent foci in the kidneys and other organs of a still-born fetus. MISCELLANEOUS ORGANISMS OF SUPPURATION DESCRIBED MORE FULLY ELSEWHERE. Before leaving the subject, attention must be directed to other bacteria that under exceptional circumstances become the cause of suppuration. Among these are the pneumococcus of Fränkel and Weichselbaum, the typhoid bacillus, and the Bacillus coli communis. These organisms are considered under separate and appropriate headings, to which the reader is advised to refer. "Centralbl. f. Bakt. u. Parasitenk." 1903, XXXIII, p. 471. CHAPTER II. MALIGNANT EDEMA. BACILLUS DEMATIS MALIGNI (KOCH). General Characteristics.-A motile, flagellated, sporogenous, anaërobic, liquefying, aërogenic, non-chromogenic, pathogenic bacillus of the soil, readily stained by the ordinary methods, but not by Gram's method. This organism was originally found by Pasteur* in putrescent animal infusions and called by him (1875) Vibrion septique. It was later more carefully studied and described by Koch.† Distribution. The organism is widely distributed in nature, being commonly present in garden earth. It is also found in dust, in waste water from houses, and sometimes in the intestinal canals of animals. Morphology. The bacillus of malignant edema is a large rod-shaped organism with rounded ends, measuring 2 to 10 μ by 0.8 to 1.0 μ. It is usually motile, and possesses many flagella. It produces oval endospores centrally situated and giving a barrel shape to the parent bacillus. Staining. The bacillus stains well with ordinary cold aqueous solutions of the anilin dyes, but not by Gram's method. Cultivation. The organism is a strict anaërobe, but under conditions by which provision is made for the removal of oxygen, grows well both at the room temperature and at that of the incubator. It is not difficult to secure in pure culture, being most easily obtained from the edematous tissues of guinea-pigs and rabbits inoculated with garden earth. The colonies which develop upon the surface of gelatin kept under anaerobic conditions appear to the naked eye as small shining bodies with liquid, grayish-white contents. Under the microscope they appear filled with a tangled mass of long filaments which under a high power exhibit *"Bull. Acad. Med.," 1877 and 1881. "Mittheilungen aus dem kaiserl. Gesundheitsamte," 1, 53. active movement. The edges of the colony have a fringed appearance, much like the colonies of the hay or potato bacillus. In gelatin and agar-agar tube cultures the characteristic growth cannot be observed in a puncture, because of the air which remains in the path of the wire, unless the tube be placed under anaerobic conditions. The best preparation, therefore, is made by heating the gelatin to expel any air it may contain, inoculating it while still liquid, and solidifying it in cold (iced) water. In such a tube the bacilli develop in globular circumscribed areas of cloudy liquefaction Fig. 113--Bacillus of malignant edema, from the body-juice of a guineapig inoculated with garden earth. X 1000 (Fränkel and Pfeiffer). marked. which contain a small amount of gas. In gelatin to which a little grape-sugar has been added the gas production is The gas is partly inflammable, partly not. A distinct odor accompanies the gas production, and is especially noticeable in agar-agar cultures. In bouillon diffuse clouding occurs, followed by the formation of a sediment. No surface growth occurs. Milk is slowly coagulated. It grows well upon the surface of potato and blood-serum under conditions of strict anaërobiosis. Metabolic Products. Of the toxic products of the organism nothing definite is known. It decomposes albumin, forming fatty acids, leucin, hydroparacumaric acid, and an oil |