104 MICRO-ORGANISMS AND DISEASE. [CHAP. 



Bull, de I'Acad., 1881 ; Eng. black leg, quarter-evil). This 

 disease, which is not uncommon in cattle, generally ends 

 fatally and is very infectious. It is characterised by hsemorr- 

 hagic effusion (or " tumour ") in the subcutaneous and inter- 

 muscular tissues of one or other, or both, anterior or posterior 

 extremities, in consequence of which the movements of the 

 animal so affected become greatly impeded. The animals 

 generally die in the course of the second or third day after in- 

 fection. The subcutaneous tumour contains numerous bacilli, 

 as do the abdominal and thoracic viscera. 



The bacilli are about the size of those of malignant anthrax 

 or a little thicker ; they are rounded at their ends and often 

 include at one end a bright oval spore ; this is also present in 

 the bacilli of the parenchymatous organs (as will be shown 

 below, this never occurs in the bacillus of malignant anthrax). 

 The bacilli are either single or form short chains. Some of 

 the bacilli are motile. 



Inoculations with them into the subcutaneous tissue of 

 guinea-pigs, rabbits, sheep, and calves always prove fatal, the 

 same subcutaneous hgemorrhagic effusions being produced. 



FIG. 72. BLOOD OF A GUINEA-PIG DEAD OF SYMPTOMATIC ANTHRAX. 



Blood-corpuscles and between them several bacilli. 

 Magnifying power 700. (Stained with Spiller's purple.) 



Injections of small quantities of bacillus-containing material 

 into the veins produces only a slight febrile disorder ; large 

 doses produce death. Animals in which by intravenous in- 

 jection of small doses slight illness has been produced are 

 afterwards protected against the fatal dose. But minimal 

 doses injected subcutaneously also produce only a slight 



