BACILLUS MALLEI 405 
nodules are stained })y Gram's method and b\' Loffler's alkaline 
methylene blue. The organism is Gram-negative, and frequently 
exhibits a beaded appearance not unlike that of the diphtheria bacillus. 
A diagnosis based upon pm-ely morphological characters is not relia})le. 
2. 6*?//f//m/.— Scrapings from unopened granulomata or from the 
organs postmortem should be inoculated upon potato having an 
alkaline reaction. The characteristic appearance of the growth upon 
this medium is suggestive, but not conclusive. B. pyocyaneus grows 
very similarly. Pus must be plated upon glycerin agar or blood 
serum, because the discharges from ulcers and abscesses are almost 
invariably contaminated with other organisms. Pure cultures are 
examined microscopically and injected into male guinea-pigs intra- 
peritoneally. 
3. Animal Injection.— The intraperitoneal injection of suspected 
material into the peritoneal cavity of male guinea-pigs leads, in the 
absence of organisms capable of causing a violent peritonitis, to the 
localization of the bacilli in the testes, wdiich become inflamed and 
swollen— the Straus reaction. The animal usually dies within a 
week. Potato cultures and microscopic examination of the purulent 
material in the testes usually suffices to establish the diagnosis. In 
case the material for examination is contaminated with other bacteria 
it is advisable to inoculate it into the subcutaneous tissues of one 
guinea-pig, and to inoculate a second male pig with material from an 
enlarged lymph gland of the first pig. A negative examination is 
inconclusive. 
Serological Diagnosis. — (a) J/fl//ei«.— Discussed above. 
(6) Ophthalmo Reaction.— The instillation of a few drops of mallein 
into the conjunctival sac of a glanderous horse leads to a reaction 
very similar to the ophthalmo-tuberculin reaction in man, except 
that in positive cases a purulent discharge as well as a red inflamed 
conjunctiva results.^ 
(c) Agglutination Te^^.— Specific agglutinins for B. mallei appear 
in the blood of infected animals, usually within four to seven days in 
acute glanders, and there is a rough parallelism between the severity 
of the disease and the development of the immune bodies. The agglu- 
tinins as a rule diminish considerably if the disease becomes chronic, 
and may become reduced to such a degree that the reaction becomes 
unreliable. The sera of normal horses frequently contain non-specific 
agglutinins which may clump glanders bacilli in dilutions of 1 to 100 
to 1 to 300. Injections of mallein appear to influence antibodies 
specific for the glanders bacillus adversely, consequently serological 
examinations should be made before mallein is injected. 
Serum for agglutination tests should be withdrawn in a sterile 
syringe from the jugular vein in the horse, and from the median basilic 
vein in man. The serum, separated from the clot, is diluted with a 
1 Meyer: Jour. Inf. Dis., 1913, 12, 170. Ferry: Jour. Am. Vet. Med. Assn., October, 
1916. 
