252 PUBLIC HEALTH BACTERIOLOGY 



lymphangitis, and then a general infection resembling a 

 pyaemia. As in the horse, the nasal mucosa tends to 

 become affected. At times the course is more chronic. 



In the horse, the infection is usually by the mucous 

 membrane of the nose or mouth, by wounds, or at times 

 by the alimentary canal. 



Toxin. No soluble toxin is described, but a concentrated 

 three-weeks' culture in glycerin broth, sterilized by heat 

 and filtered, is used as a diagnostic agent under the name 

 of mallein (fluid). Dry mallein has been prepared by 

 filtering a broth culture, concentrating filtrate on a water- 

 bath to one-tenth of its bulk, and precipitating with 

 thirty times its bulk of alcohol. Mallein differs from many 

 other bacterial extracts in being extremely resistant to 

 heat and storage without loss of strength ; 120 C. has no 

 destructive effect on it. 



Diagnosis of Glanders. Three tests are used, namely : 

 (i) Guinea-pig inoculation ; (2) Mallein test ; (3) Agglu- 

 tination test. 



1. Inoculation of a Guinea-pig. A male guinea-pig is 

 injected intraperitoneally with fragments of the diseased 

 tissue, scrapings from ulcers, or nasal discharge of the 

 suspected animal. 



A positive reaction is shown by the testicles becom- 

 ing red and swollen usually on the second or third day, 

 due to inflammation of the tunica vaginalis. Severe 

 general symptoms follow, and death occurs in twelve to 

 fifteen days. Greyish nodules are found in the spleen and 

 other organs. The test is not absolutely specific, but is 

 useful when other tests are inapplicable. A culture on 

 potato of the pus from the tunica vaginalis should be 

 made. 



2. Mallein Test. A proper dose of mallein is infected 

 subcutaneously into the breast or neck of the suspected 

 animal. It is advissd to inject a dose into a control 

 animal. The temperature of the animal should be taken 

 at least three times a day for one or two days before 

 injection. The injection is made at 6.0 to 7.0 a.m., and 

 the reaction will be at its height at or before 10 p.m. of the 

 same day. The temperature is taken every two hours 

 after the injection for at least eighteen hours. On the 



