ANTHRAX 157 



Hospital, Paris. The preliminary report of this committee 

 which was presented on September 28, 1897, is on the 

 whole unfavourable. 



ANTHRAX. 



Discovery and morphology of the organism — Growth on media — Stain- 

 ing of the bacilli — -Kesistanoe of the bacilli and spores to external 

 influences — Pathogenesis — Report of the Anthrax Committee — Infec- 

 tion from imported hides — Protective vaccination for cattle — 

 ' Attenuation ' of the organisms — Practical disinfection. 



In 1849 PoUender observed in the blood of animals which 

 had died of anthrax certain rod-like bodies. These were 

 afterwards seen by Koyer and Davaine in 1850, and by 

 Branell in the blood of a man in 1857. Davaine worked 

 with this organism from 1863-73 ; Koch in 1876 succeeded 

 in growing it outside the living body and establishing 

 its pathogenicity. 



The anthrax bacillus is the largest of all pathogenic 

 bacteria ; in length it varies from 5 to 6 n, in breadth 

 from 1 to 1'5 ytt. It is aerobic, although not strictly so, 

 for it will grow without the presence of free oxygen, viz., 

 in the blood of animals and in ' stab ' cultures. It is not 

 motile, is usually straight, and has square ends, which are 

 very characteristic. In the blood, where it occurs singly 

 or in short chains, the ends of the bacillus are very slightly 

 convex, and when stained sometimes show a central longi- 

 tudinal mark more deeply stained than the rest of the 

 protoplasm. In wool-sorter's disease the organism occurs 

 in the fluid of the lungs in long threads, generally without 

 any appearance of segmentation. 



When growing, the bacillus elongates, and then gradu- 

 ally divides transversely in the middle, the two bacilli thus 

 formed being enclosed in a common sheath. Under favour- 



