EXPERIMENTAL INOCULATION. 



309 





be only very sparsely scattered in organs such as the spleen 

 (which is often not enlarged), the lungs, or kidneys. Neverthe- 

 less the cellular structure of the organs even in such a case may 

 show changes, a fact which is important when we consider the 

 essential pathology of the disease. 



Experimental Inoculation. Of the animals commonly used 

 in laboratory work, white mice and guinea-pigs are the most: 

 susceptible to anthrax, and are generally used for test inocula- 

 tions. If a small quantity of anthrax bacilli be injected into the 

 subcutaneous tissue of a guinea-pig a fatal result follows, usually 

 within two days. Post mortem around the site of inoculation the 

 tissues, owing to 



intense inflam- ^ ' 



matory oedema, 

 are swollen and 

 gelatinous in ap- 

 pearance, small 

 haemorrhages 

 are often pres- 

 ent, and on mi- 

 croscopic exami- 

 nation numerous 

 bacilli are seen. 

 The internal 

 organs show 

 congestion and 

 cloudy swelling, 

 with sometimes "** % 



small haemor- 



, ji. FIG. 112. Portion of kidney of a guinea-pig dead of anthrax, 



rnageS, and their showing the bacilli in the capillaries, especially of the glomeru- 



CapillarieS COn- lus ' Paraffin section ; stained by Gram's method and Bismarck- 



. brown. XSOQ. 



tain enormous 



numbers of bacilli, as has already been described in the case of 

 the ox (Fig. 112); the spleen also shows a corresponding condi- 

 tion. Highly susceptible animals may be infected by being made 

 to inhale the bacilli or their spores, and also by being fed with 

 spores, a general infection rapidly occurring by both methods. 



Anthrax in the Human Subject. As we have noted, man 

 occupies a middle position in the scale of susceptibility to 

 anthrax. It is always communicated to him from animals, 



