260 Manual of Veterinary Microbiology. 



When glanders is inoculated to tlie dog or guinea 

 pig by scarifications it may be followed by a negative 

 result. Hence, an absolute value should be assigned 

 only to positive results, and the suspected material 

 which has been unsuccessfully inoculated submitted 

 to further tests. 



Diagnosis of doubtful cases. — Besides experimental 

 inoculations to susceptible animals, guinea pigs, dog, 

 and ass, and the cultures on potato of the suspected 

 discharge, some have counseled the employment of 

 auto-inoculation. This operation consists in inocu- 

 lating a horse with the products, supposed to be viru- 

 lent, coming from the same animal ; these insertions are 

 made in the skin by puncture or superficial incision and 

 the existence of glanders confirmed if the operation is 

 followed by the formation of a chancre; but, as we 

 shall see later, no conclusion can be reached founded 

 on the absence of the ulcerous reaction. In default 

 of any discharge some have resorted to extraction of 

 a swollen lymph node and examination of the same 

 for the specific bacilli. Finally, we may have re- 

 course to test inoculations with mallein. 



Mallein. — By this name is designated a glycerin 

 extract of pure cultures of the bacillus of glanders. 

 This is the glanders lymph, the analogue of the 

 tuberculosis lymph or tuberculin. The extract is 

 sterilized by heat, and diluted to ten times its weight 

 with two per cent carbolic solution. 



The injection of SO to 50 centigrams of this 

 dilution to glanderous horses produces a reaction 

 characterized especially by dejection, acceleration of 

 the pulse, and elevation of temperature ranging from 

 1*5° to 2°, by a hot cedematous swelling as large as 



