In its natural environment, those at risk are people who work with livestock. Contaminated meat causes coal-black watery malignant ulcers within two hours. Severe blood poisoning will follow. Pictures of people whose arms were soaked in infected animal blood resemble partially blackened corpses with huge blisters. Inhaled, a similar sort of thing happen to the lungs.
Anthrax simply infests the body and destroys it ability to function.
Serious study of botulinus toxin as a military agent did not occur until the 1930s, when the father of the Japanese chemical and biological program, Shiro Ishii began a study program in China during 1935. He had been impressed by a naturally occurring epidemic of cholera among Japanese troops a few months prior. Ishii established a research center in Manchuria for the study of militarily significant diseases and toxins. The first experiments were on draft animals, then on prisoners. Later, a British chemical lab at Porton Down was constructed to isolate and develop strains of clostridium botulim .