484 THE GLANDERS BACILLUS 



SECTION III. BIOLOGICAL PROPERTIES. 

 1. Viability and Virulence. 



Viability. The glanders bacillus is a delicate organism. Cultivations of 

 the bacillus kept at 37 C. die out in abcnt a month, and exposure to a tem- 

 perature of 55-60 C. will sterilize them in a few minutes. Bacilli in pus 

 are rapidly killed by desiccation, and if some glanders pus be spread in a 

 thin layer and left at the ordinary temperature of the atmosphere for 48 hours 

 it will no longer produce an infection on inoculation. In the tissues and 

 internal organs the bacillus is more resistant but can be destroyed by exposure 

 to a temperature of 100 C. for a few minutes. 



The glanders bacillus is also readily killed by antiseptics so that an exposure 

 to any of the following solutions for a few minutes will sterilize it O'l per 

 cent, acid solution of perchloride of mercury, 3 or 4 per cent, solution of 

 cresol, or solutions of carbolic acid. 



Virulence. The virulence of a given culture of the bacillus is said to 

 disappear in a week. If frequently sub-cultivated on artificial media the 

 virulence will be found to have considerably diminished by the fifth or sixth 

 sub-culture. Young cultures of recently isolated organisms are very virulent 

 and a certain amount of risk attaches to the manipulation of them. 



The virulence of the bacillus is readily increased by passage through 

 certain animals. 



Gamaleia raised the virulence of the bacillus considerably by passage through 

 ground squirrels. Protopopoff exalted the virulence by passage through rabbits 

 and found that after several passages the virulence became fixed, so that on inocula- 

 tion beneath the skin rabbits invariably died in from 5-8 days. Trasbot has brought 

 forward certain facts which seem to show that the virulence is increased by passage 

 through lions. 



2. Toxin. 



Cultures of virulent strains of the glanders bacillus sterilized at 100 C. 

 exhibit toxic properties and quickly kill the inoculated animal. The toxin 

 of glanders has not been isolated, but was made the subject of study first by 

 Kalning and Helman and afterwards by Protopopoff, by Roux and Nocard, 

 and by others. The term mallein has been applied to an extract of glycerin- 

 broth cultures of the bacillus. 



Preparation of mallein (Nocard). For the preparation of mallein an 

 organism the virulence of which has been raised and fixed by passage through 

 rabbits (intra-venous inoculation) should be used. Sow a glycerin-broth 

 medium with the infected rabbit's blood and incubate at 36 C. for one 

 month ; then sterilize the culture by heating it at 100 C. for half an hour, 

 evaporate on a water bath to one-tenth its original volume and filter through 

 Chardin paper. The brown syrupy filtrate constitutes crude mallein, 1 c.c. 

 of which is sufficient to kill a 'rabbit. 



If the crude product be treated with several volumes of alcohol a preci- 

 pitate is thrown down containing the active principle mixed with other 

 substances (dry mallein of Foth). 



Mallein in the diagnosis of glanders (Nocard). Nocard was able to demon- 

 strate a very peculiar property of mallein. If inoculated in a very small 

 dose into an healthy animal it leads to no symptoms, but if the same dose be 

 administered to an animal suffering from glanders a sharp reaction is pro- 

 duced similar to the reaction following the inoculation of tuberculin into a 

 tuberculous animal. If O25 c.c. of mallein be inoculated into an healthy 

 horse no effect is produced, but if a similar inoculation be given to a glandered 



