802 MICROBIOLOGY OF DISEASES OF MAN AND DOMESTIC ANIMALS 



the disease was made by Chabert about 1800. Pollender in 1849 

 Rayer and Davaine in 1850 reported that they had seen " filiform 

 bodies" in the blood of animals which had died of anthrax, and in 1860 

 Davaine announced he had succeeded in transmitting the disease to 

 healthy animals by inoculating them with blood from an anthrax in- 

 fected animal, and asserted that these filiform bodies or bacteria were 

 the cause of the disease. This result was attacked, and for ten years 

 there was a fierce controversy over this idea, which was finally stilled 

 by the convincing experiments of Robert Koch in 1876. Koch culti- 

 vated the bacterium of anthrax from the blood, showed that the inocu- 

 lation of these cultures in susceptible animals produced anthrax, worked 

 out the life history of the organism, and enunciated the cardinal require- 

 ments which constitute the proof of the pathogenic nature of an organ- 

 ism, what later bacteriologists have named the rules or postulates of 

 Koch. 



GEOGRAPHICAL DISTRIBUTION. The disease is very widespread, 

 occurring all over the world in tropic, semitropic, and temperate cli- 

 mates. Wherever stock are found in large numbers anthrax is usually 

 present. The disease ravages the herds and flocks in Russia, Siberia, 

 India, Argentina and parts of Hungary, France and Germany. Local 

 epidemics occur constantly in England, Canada and the United States. 

 In the delta of certain rivers the organism probably grows in the soil 

 as in the deltas of the Mississippi and Bramaputra, and the disease is 

 also common along the banks of many rivers (Vistula, Rhine, Seine, 

 etc.). 



The anthrax organism is a large, non-motile rod, from $/* to ioju long and iju to 

 1.5/i broad. In cultures it frequently forms long threads or filaments (Fig. 167). 

 The free ends are slightly rounded, but those in contact are quite square, and 

 slightly larger in diameter than the middle of the cell. Involution forms are 

 obtained by culture on potato or at temperatures of 40 to 42. It forms oval spores 

 without distortion of the mother cell (Fig. 168). Free oxygen is necessary for the 

 development of these bodies, and a temperature between 18 and 41. Spore ger- 

 mination is polar. By culture at 42 an asporogenous variety is formed. It stains 

 readily with the aniline dyes and also by Gram's method. Under certain conditions 

 a capsule may be seen. The organism is aerobic, in the body it grows as a faculta- 

 tive anaerobe. Its optimum temperature is 37, minimum 12, maximum 45. 

 It forms characteristic wavy and filamentous colonies on gelatin and agar, it liquefies 

 gelatin, produces an arborescent growth in gelatin stab cultures, coagulates and 

 peptonizes milk with an alkaline reaction. Thermal death-point of the spores in 



