DR. LEGEAR'S STOCK BOOK. 263 



ultimately burst and discharge a thin yellowish viscid material. 

 They may heal after a time, but are generally replaced by others. 

 Both forms of the disease are incurable, and dangerous to other 

 animals and to man. 



Diagnosis. By reading the above it will be seen that it is im- 

 possible to diagnose with any degree of certainty a great many 

 cases of glanders by mere physical examination. In 1891, Pro- 

 fessors Kalning and Helman, of Russia, discovered a substance 

 called mallein, which has rendered wonderful service in detect- 

 ing doubtful and suspicious cases of glanders. During the short 

 time since the discovery of mallein it has been tested by leading 

 scientific veterinarians in every part of the world, and all unite 

 in asserting that its use has at least furnished us with an agent 

 by which we can readily and safely diagnose the disease, not only 

 in suspected cases, but in those animals where the most care- 

 ful physical examination can detect no signs of the disease. In 

 the annual report of the Bureau of Animal Industry may be 

 found the following: 



"Glanders is a contagious and incurable disease of horses, more 

 widespread than is generally supposed. It is also communicated 

 to man from affected horses, and is then nearly always fatal in 

 its results. This disease has been allowed to spread without ade- 

 quate efforts for its control, until it can now be found in nearly 

 every city of any considerable size and in many country districts. 

 The greatest obstacle to its eradication heretofore existing was 

 the difficulty of making a positive diagnosis in many suspected 

 animals. With many affected horses the symptoms are obscure 

 and indefinite, but the power to communicate the disease is just 

 as marked as those having the most apparent symptoms. For- 

 tunately it has been shown by recent researches that the bacillus 

 of glanders produces a substance during its growth in culture 

 liquids similar to the tuberculin produced by the bacillus of 

 tuberculosis, and that this substance, which is called mallein, 



