like those of the Bact. coli. In the gelatin stab there is a feeble growth; the surface growth is porcelain white, markedly lobulated, and after ten hours sinks into a depression. Upon potato a dry growth. Nutrient fluid uniformly cloudy, without a pellicle or with a scanty one. Spirillum stomachi. (Salomon.) L. and N. Salomon has described (C. B. XIX, 433,) a very interesting beautiful spirillum, which has not been cultivated, and is never absent from dogs' stomachs. It is also found in cats and rats, and can be readily transferred to mice by feeding. It occurs especially in the glands of the stomach. 3. Spirochete. Ehrenberg. The cells are flexible, and present long, pointed, spirally bent threads. Flagella are unknown. Motility is assigned to an undulating membrane. A key for their differentiation may be omitted, since only two or three species are known. Spirochete Obermeieri. F. Cohn.1 (Plate 56, VIII and IX.) Literature.-Obermeier (C. f. med. Wiss., 1873, 145); Koch (Mitt. a. d. Ges.-Amte, I, 167); Soudakewitsch (A. P. v, 545); Cohn (Beiträge, I, Heft III, 196); literature by Afanassiew (C. B. xxv, 415). The personal investigations of these authors are not adapted for use in a text-book. Bacteriologically very little is known. Large, flexible, motile threads, coiled like a corkscrew, with pointed ends, 1 to 26 times as long as the diameter of a blood-cell, usually 20-30 μ. Flagella and spores are not known. 1 Sakharoff discovered, in the blood of geese suffering from an epizootic disease in Caucasus, a motile but not flexible spirochete, Spirochete anserina Sakharoff (C. B. x1, 203),—through which the disease may be transferred to healthy animals. Details are given regarding it by Gabritschewsky (C. B. XXIII, 365). It was not cultivated. The following may be simply mentioned: Spirochete plicatilis Ehrenberg from marsh-water and the Spirochete of the saliva, which have been often seen but never cultivated. According to F. Cohn (Beiträge, Bd. 1, Heft II, and Heft III, pp. 197, 199), these varieties are not to be distinguished microscopically from the Spiroch. Obermeieri. It is typically found in the blood and spleen of recurrent fever cases, hardly ever during the afebrile periods (an exception proved by Naunyn); demonstrated by Karlinski to be the cause of a part of the cases of febrile icterus (C. B. XI, 26). It stains readily with the usual anilin dyes. Günther recommends that the dried and fixed preparation be previously freed of part of the albuminous bodies by means of a 1% to 5% acetic acid solution. It is not stained by Gram's method. No cultures have so far been successful. According to Pasternatzky, the spirochete may be preserved alive for about ten days if a leech is allowed to fill itself from a case of recurrent fever, and then is kept upon ice. Inoculation experiments have succeeded only upon man and monkeys. The monkeys become sick after about three and a half days, but present only the initial attack of fever and no recurrence. Extirpation of the spleen makes the disease more dangerous for the monkey. APPENDIX I. Actinomycetes. For the limitation of this group and its genera, see page 127. We have conscientiously recorded all that is known to us in the literature regarding forking, branching, etc., in other forms up to this time considered as true bacteria; thus, B. pyocyaneum, B. influenza, B. tetani, B. radicicola, Vibrios,-the cladothrix form of B. murisepticum was immediately retracted by Kitt himself,—and we must naturally acknowledge that these observations make it more difficult to perceive in the branching a distinguishing peculiarity between actinomycetes and fission-fungi. Innumerable similar difficulties are, however, encountered in the definition of higher plant families-some genera are often placed with equal propriety in one or another family. If at a later time, because of further investigations, the significance of branching should be construed in a manner different from that of to-day, it will still remain true in any case that the actinomycetes of to-day, which we have collected in part upon the basis of branching, will form a perfectly natural family, even if their family diag nosis should be essentially remodeled. 1. Corynebacterium. Lehm. and Neum. Cultures having throughout the character of cultures of true bacteria; soft, lying flat and loose upon the nutrient media. Stain well with the ordinary bacterial stains, but are not acid proof. Microscopically: Rods, which frequently present clubbed swellings at the ends, appear more or less distinctly composed of differently staining segments, and in many cultures present constantly an undoubted, true branching. Key to the Recognition of the Most Important Varieties of the Genus Corynebacterium. 1. Plate cultures upon gelatin: Colonies like those of Bact. coli or typhi-i. e., roundish, and when magnified sixty times, with distinct lineal markings; upon agar and serum-agar, just like Bact. coli. Potato culture brownish-red. Cause of glanders. Corynebact. mallei L. and N., page 384. 2. Plate cultures upon agar and serum-agar with very characteristic granulation (splintery!). Growth upon potato usually slight. Colorless to yellowish. (a) Very luxuriant growth upon the nutrient media, even upon potato. Gelatin gradually discolored brown. Growth often yellowish, sometimes brownish. Not pathogenic for animals. Usually little acid produced in bouillon. Usually no granules in the rods when stained by Neisser's method. Corynebact. pseudodiphtheriticum (Hofmann-Wellenhof) L. and N., page 404. (b) Growth of medium intensity upon agar, and best upon serumagar; poor upon gelatin and potato. Vigorous production of acid in bouillon. Usually granules in the rods when stained by Neisser's method. Pathogenic for man and animals. Corynebact. diphtheria Löffler, L. and N., page 389. (c) Scanty growth upon nutrient media. No production of acid in bouillon. No granules staining by Neisser's method. Not pathogenic. Corynebact. xerosis (Neisser and Kuschbert) L. and N., page 406. The close relationship of Corynebacterium diphtheria with Coryn. pseudodiphtheriticum and Coryn. xerosis permits no certain recognition from this key alone. (Compare p. 403.) Corynebacterium mallei. (Löffler and Schütz.) (Plate 57.) Common Names.-Glanders bacillus; German, Rotz; Latin, malleus; French, morve; English, glanders. Bacillus mallei Flügge. Principal Literature.-Löffler (A. G. A. 1, 141). Kranzfeld (C. B. II, 273). Kitt (C. B. II, 241). Microscopic Appearance.-Slender rods (2-3 μ long, 0.4 thick), sometimes with brightly shining bodies (metachromatic bodies), which may be shown very well by means of Neisser's staining method for diphtheria granules. True endogenous spores are never present; all previous positive statements to the contrary are erroneous. In old cultures clubbed, vesicular enlargements which create the impression of involution forms are often seen; also long threads, which sometimes exhibit true branching (57, XII) in great abundance. See Semmer (C. B. XVIII, 68). Dissertation by Erich Wolf, Würzburg, 1898, and Marx (C. B. xxv, 274). Staining Properties. Somewhat difficultly with ordinary stains; does not stain by Gram's method. For staining the bacteria in sections, Nicolle's method is to be recommended (Technical Appendix). Requirements as Regards Composition of Nutrient Media, Supply of Oxygen, and Temperature.—Grows best at incubator temperature (minimum, 25°; maximum, 40°). Prefers glycerin-agar to ordinary agar, but is not particular. Grows well aerobically, poorly or not at all anaerobically. Gelatin Plate.-(a) Natural size. Superficial and deep colonies: Small, whitish, punctiform; also after a long time they do not become essentially larger. The superficial ones have a delicate, transparent halo (57, v). (b) Magnified sixty times. Superficial: Irregularly roundish; scalloped, wavy margin; shining white, transparent, with wavy elevations and marked reflex. Old colonies are more yellowish, especially in the center, with linear, depressed markings. They are very similar to colonies of B. typhi and putidum in the early stages (57, viii, e). Deep Roundish or oval; sharply outlined; in the center delicately crumbly, at the outer part streaked. The peripheral zone is sharply marked (57, VIII). Gelatin Stab.-Stab: Thread-like; sometimes faintly granular, sometimes like a string of pearls; gray. Surface growth: Exceedingly delicate, perfectly transparent, gray, with a ragged fringe, and of a dull luster (57, 1). Agar.-Not distinguishable from Bact. coli; entirely non-characteristic (57, IV, VII). For a year we cultivated a form of the Cory. mallei, which occurred spontaneously and which produces rusty-brown colonies upon agar. This is |