=Mallein (Toxin of Glanders).=--Among the soluble products secreted in the culture media by the glanders bacilli, there are found true toxins to which are ascribed certain symptoms of glanders infection. These toxins have been isolated and designated by the name _mallein_. First prepared by Helman and Kalmino, mallein was later on specially studied by Roux and Nocard, and, in consequence of the researches of the last-mentioned scientist, it has acquired great importance.[126] It is obtained by sterilizing at 110° C. cultures of the glanders bacillus made with mutton bouillon with the addition of salt, glycerin, and peptones. To isolate the toxin the culture bouillon is first sterilized by heating for half an hour in an autoclave at 100° C. It is then filtered, concentrated to one-tenth its volume on a water-bath, and filtered through a Chardin filter. The mallein is thus obtained in the form of a brown syrupy liquid containing half its weight of glycerin. [126] NOCARD: _Les Maladies microbiennes des animaux_, Paris. This solution keeps well when kept from air, light, and heat. In practice it is employed in 10-per cent. solution in phenolated water (5:1000). The mallein may be precipitated from the crude solution by the addition of alcohol, as recommended by Foth. Foth's mallein occurs as a white, light powder, very easily soluble in water. Mallein enjoys a very important rôle in veterinary therapeutics, a rôle analogous to that of tuberculin, permitting the diagnosis of incipient glanders.[127] [127] STRAUSS: _Arch. de Médic. expériment_, 1886. Experience has shown that in animals already attacked by glanders, even if ever so slightly, the thermic reaction never fails when 0.25 Cc. of the mallein solution is injected. In healthy animals, however, the injection of mallein, even in much larger quantities, causes no apparent effect. In animals attacked by glanders the reaction attains its maximum in twelve hours, and several days are required for the temperature to return to normal.[128] [128] CADIOT and ROGER: _Compt. rend. Soc. Biol._, 1895, p. 770; WLADIMIROW: _Arch. des Sciences Biol. de St.-Pétersbourg_, IV, p. 30; BOURGES and MÉRY: _Soc. de Biol._, Feb. 5, 1878. According to Nocard, mallein possesses no immunizing properties whatever.[129] [129] GALTIER: _Compt. rend. de l'Acad. des Sciences_, XCII, p. 303; STRAUSS: _Arch. de Médic. expériment_, I, p. 489. =Typhoid Toxin.=--This is obtained, like the other microbial toxins, from a culture, prepared with more or less difficulty, from Eberth's typhoid bacillus. This toxin, injected into guinea-pigs, develops in them typhoid fever. In the solution there occurs a ptomaine, which has been isolated by Brieger, and which gives rise to almost all the phenomena of typhoid fever; this ptomaine is called _typhotoxin_.[130] [130] BRIEGER: _Microbes, Ptomaïnes et Maladies_, Doin, publ., Paris, 1887; LUFF: _Brit. Med. Journ._, 1889.