STAINING IN TISSUES. 395 



it displays in the horse and ass. The clinical and path- 

 ological manifestations resulting from inoculation of 

 guinea-pigs are much more faithful reproductions. The 

 animal lives usually from six to eight weeks after inocu- 

 lation, and during this time becomes aifected with a group 

 of most interesting and peculiar pathological processes. 

 The specific inflammatory condition of the mucous 

 membrane of the nostrils is almost always present. The 

 joints become swollen and infiltrated to such an extent 

 as often to interfere with the use of the legs. In male 

 animals the testicles become enormously distended with 

 pus, and on closer examination a true orchids and epi- 

 didymitis are seen to be present. The internal organs, 

 particularly the lungs, kidneys, spleen, and liver, are 

 usually the seat of the nodular formations characteristic 

 of the disease. From all of these disease-foci the 

 bacillus causing them can be isolated in pure culture. 



STAINING IN TISSUES. Though always present in 

 the diseased tissues, considerable trouble is usually 

 experienced in demonstrating the bacteria by staining- 

 methods. The difficulty is due to the fact that the bac- 

 teria are very easily decolorized, and in tissues stained 

 by the ordinary processes are robbed of their color even 

 by the alcohol with which the tissue is rinsed and de- 

 hydrated. If we will remember not to employ con- 

 centrated stains, and not to expose the sections to the 

 stains for too long a time, but little treatment with 

 decolorizing-agents is necessary, and very satisfactory 

 preparations will be obtained. A number of methods 

 have been suggested for staining the glanders bacilli 

 in tissues, and if what has been said will be borne in 

 mind, no difficulty should be experienced. 



Two satisfactory methods that we have used for this 



