VACCINE THERAPY AND PROTECTIVE INOCULATION 257 



ago by Feser, who found bacilli like the black-leg bacillus in such 

 mud and succeeded in producing the disease by inoculation into 

 cattle and sheep. Cases of black-leg have been seen following cas- 

 tration. It is also held that the disease may be contracted by infected 

 water or feed. Marek saw a case in a hog in which the infection had 

 occurred through the tonsils. The black-leg bacilli appear to live 

 and multiply as saprophytes in the soil. Direct transmission from 

 one animal to another does not appear to occur. In infection through 

 the intestines it is believed that spores enter the lymph and blood 

 currents and are carried by them to some place in a muscle or in 

 loose connective tissue, where aerobic bacteria have gained entrance 

 through a wound. With these the black-leg bacillus, or its spores, 

 enters into a symbiotic community, and the organism is now enabled 

 to multiply and produce the disease. 



Resistance. The spores of the Bacillus sarcophysematos bovis 

 are highly resistant. Sporulating bacilli contained in pieces of dry 

 meat remain virulent for many years (10). The spores resist putre- 

 factive processes for months, and they are believed to remain alive for 

 a long time in manure. Spores contained in dried pulverized meat 

 have been exposed in the steam sterilizer for five to six hours to a 

 temperature of 100 C., and have still been found very virulent. 

 Sheep have been killed by inoculating them with 0.1 to 0.2 gram of 

 material treated in this manner. It requires fully seven hours in 

 streaming steam of 100 C. to kill the spores in dried meat; dry heat 

 of 104 C. has no effect after seven hours' action. Virulent spores 

 have a negative chemotactic effect upon phagocytes, but avirulent 

 spores freed of their toxins are taken up by phagocytes and destroyed. 

 If toxin-free spores, however, are protected against phagocytosis by 

 mechanical means (sand) or by chemical means (injection of lactic 

 acid) they can still germinate and produce a fatal infection. Direct 

 sunlight kills moist spores in eighteen hours; dried spores during the 

 greatest summer heat in twenty-four hours. Corrosive sublimate 

 has a comparatively strong disinfective power toward the spores; 

 1 to 500 solution kills spores from a culture in ten minutes; in moist 

 fresh meat, in thirty minutes; in dried meat, after sixty minutes' 

 exposure. The effect of carbolic acid is not very rapid; according to 

 Kitasato, a 5 per cent, solution killed spores only after ten hours. 

 The microorganism is a saprophytic soil bacterium, and its strong 

 resistance makes the disinfection of infected marshy pastures prac- 

 tically impossible; they either must be abandoned or the animals 

 having access to them must be protected by inoculation. 



Vaccine Therapy and Protective Inoculation. The first successful 

 experiments in protective methods against emphysematous anthrax 

 were undertaken by Arloing, Cornevin, and Thomas during the years 

 1880 to 1887. The first method used by French investigators consisted 

 in the intravenous injection of 1 to 6 c.c. of expressed juice from 

 infected muscles. This procedure confers immunity, but is very 

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