258 VETERINARY BACTERIOLOGY 



This method is essentially a laboratory one and quite impracti- 

 cable for field work. There seems to be no reason why blood 

 samples or, better, serum samples from suspected cases should not 

 be sent to properly equipped laboratories for diagnosis and report. 

 The method apparently is capable of giving good results, and seems 

 to be more accurate than the mallein test. 



Mallein Test for Glanders. Mallein is a suspension of killed 

 B. mallei, together with the products of its autolytic disintegration. 

 What the active principles in bringing about the characteristic 

 reaction in a glandered horse may be is not known. Probably 

 they are the soluble bacterial proteins, possibly true endotoxins. 

 The various laboratories use different methods of preparing mal- 

 lein. The most important of these are worthy of note. 



The mallein of Roux is prepared by the Pasteur Institute as 

 follows: The virulence of the B. mallei used is increased by pas- 

 sage through rabbits, and is such that mice and rabbits are killed 

 in less than thirty hours by intravenous injections. Flasks 

 containing 250 c.c. of glycerin bouillon are inoculated and in- 

 cubated a month at 35. The cultures are killed by exposure 

 to a temperature of 100 for thirty minutes in an autoclave, then 

 evaporated to one-tenth the volume, and filtered through filter- 

 paper (" papier Chardin "). The final product is a dark-brown, 

 syrupy liquid, containing 50 per cent, glycerin. For use this is 

 mixed with nine times its volume of 0.5 per cent, carbolic acid. 

 The diagnostic dose is 2.5 c.c. of this dilution. 



The mallein of Vladimiroff, used in the Russian Empire, is 

 prepared by inoculating a considerable number of flasks, each 

 containing 600 to 800 c.c. of beef broth, with a vigorous culture 

 of B. mallei, and incubating for eight months at 37. The flasks 

 are shaken from time to time to cause ohe shiny, gray-white pel- 

 licle which forms to sink to the bottom. The culture is then 

 examined for purity, sterilized in the autoclave at 110, and filtered. 

 This is concentrated and again diluted until the diagnostic dose for 

 the horse is 1 c.c. 



The mallein or morvin of Babes is prepared by inoculating 

 potato paste with B. mallei, and incubating six weeks. It then 

 is heated at 68 for three and one-half hours, emulsified with water, 

 filtered through a Witt filter, and precipitated with alcohol. This 



