304 BACTERIA 



Channels of Infection, i. The Alimentary CanaL This 

 is the usual mode of infection in animals grazing on infected 

 pasture land. A soil suitable for the propagation of anthrax 

 is one containing abundance of air and proteid material. 

 Feeding on bacilli alone would probably not produce the 

 disease, owing to the germicidal effect of the gastric juice. 

 But spores can readily pass uninjured through the stomach 

 and produce anthrax in the blood. Infected water as well 

 as fodder may convey the disease. Water becomes infected 

 by bodies of animals dead of anthrax, or, as was the case 

 once at least in the south-west of England, by a stream 

 passing through the washing-yard of an infected tannery. 

 Manure on fields, litter in stalls, and infected earth may all 

 contribute to the transmission of the disease. Darwin 

 pointed out the services which are performed in superficial 

 soils by earthworms bringing up casts ; Pasteur was of 

 opinion that in this way earthworms were responsible for 

 continually bringing up the spores of anthrax from buried 

 corpses to the surface, where they would reinfect cattle. 

 Koch disputed this, but more recently Bollinger has demon- 

 strated the correctness of Pasteur's views by isolating an- 

 thrax contagium from five per cent, of the worms sent him 

 from an anthrax pasture. Bollinger also maintains that 

 flies and other insects may convey the disease from dis- 

 charges or carcasses round which they congregate. 



Alimentary infection in man is a rare form, and it reveals 

 itself in a primary diseased state known as 7nycosis intestin- 

 alls, an inflamed condition of the intestine and mesenteric 

 lymph glands. 



2. Through the Skin. Cutaneous anthrax goes by the 

 name of malignant pustule^ and is caused by infective an- 

 thrax matter gaining entrance through abrasions or ulcers 

 in the skin. This local form is obviously most contracted 

 by those whose occupation leads them to handle hides or 

 other anthrax material (butchers and cleaners of hides). 



