GENUS BACTERIUM 237 



tutes the active principle of mallein. The toxin, or mallein, 

 belongs to the class of endotoxins. The toxic products have 

 been invariably obtained by extraction of dead bacilli. 2 Mal- 

 lein differs from many other bacterial poisons in being ex- 

 tremely resistant. It withstands temperatures of 120 C. and 

 prolonged storage without noticeable loss of strength. In its 

 physiological action on healthy animals, mallein is not a pow- 

 erful poison. It can be given in considerable doses without 

 causing death. Mallein may be obtained by a variety of 

 methods. Helman and Kalnig, the discoverers of this toxin,, 

 used filtered aqueous and glycerin extracts of potato cultures. 



Resistance. Bacterium mallei is destroyed when taken 

 from fresh cultures by an exposure at 55 C. for 10 minutes. 

 It is killed in a three per cent solution of carbolic acid in five 

 minutes; by a 1 to 500 solution of mercuric chloride in from 

 two to three minutes. Smears of the fresh cultures are de- 

 stroyed by drying in the air for a few days. Smears made 

 from glandered tissues will resist dessication for a longer time. 



Pathogenesis. This organism is the cause of glanders 

 in horses and the horse kind and in man. 3 Guinea pigs are 

 quite susceptible to inoculation. Dogs, ferrets, moles and 

 field mice are said to be susceptible, while sheep, swine and 

 rabbits are reported as less susceptible. Cattle are immune. 



Isolating Bacterium mallei from lesions. In isolating the 

 organism from lesions on the nasal septum or skin abscesses 

 (farcy buds) considerable difficulty may be experienced on 

 account of contaminating bacteria which may grow more 

 vigorously on the media than Bacteria mallei. From lesions 

 in the lungs or other organs, pure cultures can usually be ob- 

 tained on acid-glycerin-agar or potato. 



It is often necessary for the isolation of this organism to 



2 Kresling. Arch, de Soc. biol. 1892; Preuser. Berl. thierarzt. 

 Woch., 1894. 



3 Many cases of glanders in man have been reported. Coleman 

 and Ewing (Jour, of Medical Research, Vol. IX, n. s. IV (1903) p. 

 223) report a case with the study of the organism isolated. Robins 

 (Studies from the Royal Victoria Hospital, Montreal, Vol. 2 No. 1, 

 1906) has gathered the literature and reported 156 cases in man. 



