466 CHRONIC INFECTIOUS DISEASES 



the serum in such cases having a very low agglutinating 

 power. On the other hand some healthy horses possess an 

 agglutinating power as high as that found in some glanderous 

 horses. Healthy horses recently malleinized (within three 

 months) may give a positive agglutination reaction. 



Since it is the degi-ee of agglutination and not agglutination 

 itself that determines whether or not infection is present, 

 misinferpretations are unavoidable. .When the agglutination 

 test is to be employed, the veterinarian usually only collects 

 the serum under proper precautions and sends it to the 

 laboratory. 



C. Serum Diagnosis by Means of Complement Fixation. — 

 This is a laboratory method for the diagnosis of glanders 

 which seems to be very accurate. Practically, it is the 

 application to glanders of the Wassermann test for syphilis 

 in man. The test should be made by an experienced manipu- 

 lator in a properly equipped laboratory. The practitioner 

 usually only collects the sertan as in the agglutination test. 

 The results so far obtained from this method are very 

 encouraging (for details see Bacteriology). 



D. Inoculation of Experimental Animals. — For this pur- 

 pose a young, male guinea pig is chosen which is inoculated 

 intraperitoneally with an emulsion in sterile water of nasal 

 or skin ulcer discharge from a suspicious case. One to 2 c.c. 

 are injected into the abdominal cavity of the guinea pig. 

 If the bacilli of glanders are present, swelling of the scrotum, 

 followed by adhesion of the testicles, will occur in two to 

 three days. Sometimes only a skin abscess at the point of 

 inoculation appears. The danger of general septicemia 

 may be avoided by keeping the material in a refrigerator 

 for a few days before inoculation. Potato cultures should 

 always be made from the lesions in the scrotum. On potato 

 the glanders bacilli produce yellow colonies resembling honey, 

 while the pseudoglanders bacilli produce white .colonies. Posi- 

 tive evidence obtained from this method is of course much 

 more valuable than negative. Occasionally the discharge col- 

 lected, even though it comes from a glanderous animal, may not 

 contain glanders bacilli. The agglutination and complement- 

 fixation tests have largely superseded this method. 



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