INOCULATIONS OF B. DIPHTHERIA. 249 



method and the fibrin method of Weigert give excellent 

 results. 



PATHOGENIC PROPERTIES. When inoculated sub- 

 cutaneously into the bodies of susceptible animals the 

 result is not the production of a septicaemia as is seen 

 to follow the introduction into animals of certain other 

 organisms with which we shall have to deal. The 

 bacillus of diphtheria remains localized at the point 

 of inoculation, never spreading further than the nearest 

 lymphatic glands. It develops at the point in the tissues 

 at which it is deposited, and during its development gives 

 rise to changes in the tissues which result entirely from 

 the absorption into the circulation of poisonous albumins 

 produced by the bacilli in the course of their develop- 

 ment. 



If a very minute portion of either a solid or fluid 

 pure culture of this organism is introduced into the 

 subcutaneous tissues of a guinea-pig or kitten, death of 

 the animal is seen to ensue in from twenty-four hours 

 to five days. The usual changes are an extensive local 

 oedema with more or less hypersemia and ecchymosis at 

 the site of inoculation ; frequently swollen and reddened 

 lymphatic glands ; increased serous fluid in the perito- 

 neum, pleura, and pericardium ; enlarged and hemor- 

 rhagic supra-renal capsules; occasionally slightly swollen 

 spleen ; sometimes fatty degeneration in the liver, kidney, 

 and myocardium. The bacilli are always to be found 

 at the seat of inoculation, most abundant in the grayish- 

 white fibri no-purulent exudate present at the point of 

 inoculation, and becoming fewer at a distance from this, 

 so that the more remote parts of the oedematous fluid do 

 not contain any bacilli. The bacilli are found not only 

 free, but contained in large number in leucocytes, some 



