322 BACTERIOLOGY. 



usually present in enormous numbers. In the blood 

 they are practically always free, and are but rarely found 

 within the bodies of leucocytes. 



In stained preparations from the blood and exudates 

 a capsule is not infrequently seen surrounding the organ- 

 isms. (Fig. 64.) This, however, is not constant. 



Fig. 64. 



MicrocoeeuB lanceolatus in blood of rabbit. Stained by method of Gram. 

 Decolorization not complete. 



If a drop of blood from the dead animal be intro- 

 duced into the tissues of a second animal (mouse or 

 rabbit), identically the same conditions will be repro- 

 duced. 



If the organism be isolated in pure culture from the 

 blood of the animal, and a portion of this cultui'e be 

 introduced into the tissues of a susceptible animal, 

 we shall see again the same pathological picture. 



It must be remembered, however, that this or- 

 ganism when cultivated for a time on artificial media 

 rapidly loses its pathogenic properties. If, therefore, 

 failure to reproduce the disease after inoculation 

 with old cultures should occur, it is in all probability 

 due to a loss of virulence of the organism. 



