Biological weapons are a widely used source of terror. The definition of a biological weapon is a harmful biological agent (such as a pathogenic microorganism or neurotoxin) used as a weapon to cause death or disease, usually on a large scale (“Biological Weapon,” The Merriam-Webster Dictionary). There are numerous substances used as biological weapons. Some include glanders, botulism, and brucellosis. Biological weapons consist of a type of substance or disease that is used to launch an attack on a large population of people. A commonly used biological weapon is anthrax. Inhalation of anthrax is the most common way of causing harm. When someone is poisoned by inhaling anthrax, they have actually been exposed to anthrax spores. Once the spores are in the body, they infect various organs, causing mass infection and eventually collapse of the immune system. This causes death. Anthrax is used as a biological weapon because it is very deadly and difficult to detect. Anthrax is also common in nature, so it is an easy bacterium to find and spread. Anthrax is a bacterium that affects both humans and animals. Cows and other animals are very prone to being infected with anthrax. Anthrax is caused by the bacterium Bacillus anthracis: a gram-negative, facultative, anaerobic, spore-forming bacterium (Thavaselvam et al. 2). Gram-negative means that the bacterium does not retain the purple dye used in the Gram test. The Gram method is used to classify bacteria. Anaerobic refers to an organism that requires the presence of oxygen to function. Facultative refers to a bacterium that can produce ATP through aerobic respiration, but may use fermentation if oxygen is not present. There are three forms of anthrax poisoning. ...... middle of paper ......" The Merriam-Webster Dictionary. 12th ed. Springfield, Mass: Merriam-Webster, 2004. 66. Print. Chemical and biological terrorism research and development to improve civil medicine Response. Washington, DC: National Academy, 1999. Print.Coen, Bob and Eric David Nadler Dead Silence: Fear and Terror on the Anthrax Trail Berkeley: Counterpoint, 2009. Print.Koblentz, Gregory D. Living Weapons Biological Warfare.: Cornell UP, 2009. Print.Park, Alice. “How Anthrax Is Weaponized.” Spiers, Edward M. A History of Chemical and Biological Weapons. London: Reaktion, 2010. Print Thavaselvam, Duraipandian and Rajagopalan Vijayaraghavan "Biological Warfare Agents"..