GLANDERS BA GILL US. 603 



southern countries, sometimes taking a mild course and 

 remaining latent for a considerable time (Semmer and 

 Babes). Apparently healthy horses, therefore, may pos- 

 sibly spread the disease. 



Attenuation of virulence occurs in cultures which 

 have been kept for some time, and inoculations with 

 such cultures may give a negative result; or, when con- 

 siderable quantities are injected, may produce a fatal 

 result at a later date than is usual when small amounts 

 of a recent culture are injected into susceptible animals. 



Several attempts have been made by investigators to 

 produce artificial immunity against glanders, but so far 

 with unsatisfactory results. According to Strauss, dogs 

 may be protected by intravenous inoculations of small 

 quantities of living bacilli against an injection with 

 large quantities which usually kill them. Fenger has 

 found that animals inoculated with glanders bacilli 

 react less powerfully to fresh injections; and that rab- 

 bits which have recovered from an injection of glanders 

 are subsequently immune, the immunity lasting for from 

 three to six weeks. Ladowski has obtained positive re- 

 sults also in rabbits and cats by intravenous injections 

 of sterilized cultures. Other observers have reported 

 not only the production of immunity, but also cures, by 

 the use of mallein. Mallein is produced by evaporat- 

 ing a six-weeks 7 old culture of the glanders bacillus in 

 5 per cent, glycerin nutrient veal bouillon to 10 per 

 cent, of its original bulk. It is made in the same way 

 as Koch's crude tuberculin from the tubercle bacillus 

 cultures. j % . 



Differential Diagnosis. It is often difficult to demon- 

 strate microscopically the presence of the bacillus of 

 glanders in the nodules which have undergone purulent 



