Biology, Chemistry, and War Summary

  • Last updated on November 11, 2022

Science and war have always developed side by side.


Science and war have always developed side by side. New inventions were often made during war or to further bellicose goals. Scientists were tasked with inventing weapons that could kill the enemy more efficiently or ways to protect their governments’ own forces. Biology is the science of all living organisms. Biological warfare, also known as germ warfare, is the use of viruses, bacteria, or other disease-causing living organisms as biological weapons (bioweapons). Chemistry deals with the structure, composition, and properties of all kinds of matter and the reactions they may cause in interaction. The use of nonliving toxic products as weapons is considered chemical warfare. Both biological and chemical weapons can occur in nature and be employed as weapons, which tended to happen in ancient and medieval times. In modern times, science and technology have been applied to develop such weapons and the means of delivering them.Biological warfareChemical warfareBiological warfareChemical warfareDisease;as weapon[weapon]


Both biological and chemical weapons are considered to be Weapons of mass destructionweapons of mass destruction (WMDs), since they are designed to kill millions of people, and thus they pose a grave threat to humanity as a whole. Sometimes called “the poor man’s atom bomb,” the sheer existence of these weapons inflicts fear, and because the threat of their use is a potent means of intimidation, their effect can be more psychological than real. Whoever is in possession of such weapons will have the upper hand in any conflict, at least once conventional means fail, and this makes the party possessing chemical or biological weapons a potential aggressor, feared by neighbors. These WMDs not only threaten annihilation and defeat; their inhumane nature has also led to their banishment in the modern world.

History of Biology, Chemistry, and WarAncient World

Early recorded uses of bioweapons include the Poisoningpoisoning of wells by toxic plants during the FirstSacred War, First (595-586 b.c.e.)Sacred War in Greece (595-586 b.c.e.) and by the Roman commanderAquilius, ManiusAquilius, ManiusManius Aquilius in 130b.c.e. Wells were often poisoned by placing poisonous plants, dead horses, or even killed persons in them. In sea battles, catapults, or ballistae, were sometimes loaded with snakes, which were lobbed onto the decks of enemy ships and caused panic aboard that confined space.

According Smoke;weaponsto archaeological evidence, bitumen and sulfur crystals were ignited by the armies of ancient Persia to give off a dense, poisonous smoke that killed Roman soldiers. SunziSunziArt of War, The (Sunzi) Sunzi’s Sunzi Bingfa (c. fifth-third century b.c.e. ; The Art of War, 1910) and Hindu books describe ways to poison wells, create toxic smoke, and poison weapons. The effect of such weapons seems to have been limited, however.

Medieval World

In medieval times, the poisoning of wells continued. Even though the exact mechanisms of infection remained unknown, it was clear that disease could spread from animals to people or from person to person. Aggressors, when laying siege to a town, would catapult sick or dead animals into the town, hoping that the carcasses would infect the inhabitants. Victims of the Plaguebubonic plague (Black Death) or decomposing corpses were also shot into besieged towns, as were feces. During the Siege of Caffa, Siege of (1346)Caffa in 1346, the besieging Mongol forces catapulted cadavers of plague-infested animals into the city. However, the plague most likely first affected the attackers. Thousands were killed, according to eyewitnesses. The Black Death spread from there toward Constantinople, Italy, and France. It is unclear whether and to what extent the use of bioweapons contributed to this pandemic.

Gunpowder, Gunpowdera chemical invention and hence a form of chemical weapon, revolutionized warfare. Military units were now able to fight numerically superior forces, fortifications could be breached more easily, and small groups of skilled knights gave way to mass formations of riflemen.

Modern World

In the Native AmericansSmallpoxAmerican Indiansfifteenth through eighteenth centuries, Europeans colonizing the Americas, perhaps unbeknownst to them at first, brought many diseases with them to the New World, and these essentially functioned as biological weapons, even when they were not initially intended as such. Smallpox epidemics raged among indigenous Americans, and there have been allegations that British commanders spread the disease deliberately to quell Native American uprisings. While it is a fact that smallpox had a very high morbidity rate among Native Americans, because of their complete lack of immunity to the virus, and thus affected them more than the European settlers, those allegations cannot be proved in most cases. However, some evidence exists to support the intentional use of the smallpox virus against Native Americans. In 1763, during Pontiac’s Rebellion, one “Mr. McKee” and Captain Simeon Ecuyer, the commanding officer at Fort Pitt, gave “two blankets and a handkerchief out of the Small Pox Hospital” to Delaware chiefs with the “hope it will have the desired effect.”

Smallpox caused many casualties during the American Revolution (1775-1783);smallpoxAmerican Revolution (1775-1783), and there are allegations that it was spread deliberately by both sides. Again, there is no way to prove this today, and analysts still argue whether this kind of biological warfare took place or events occurred naturally. Native Americans, for their part, poisoned wells by throwing killed animals in them, a method repeated during the American Civil War (1861-1865);biological warfareAmerican Civil War (1861-1865). Additional proposals were brought forward to produce various types of chemical weapons during the Civil War, but it was thought that battlefield doctors and nurses would have a difficult time dealing with the effects of these weapons, and the proposals were shelved. Other nations drew back from chemical weapons as well. Some in the British military, during the Crimean War (1853-1856), proposed to use cyanide, but it too was rejected.

During Japan;biological weaponsthe Second Sino-Japanese War, Second (1937-1945)[Sino Japanese War, Second]Sino-Japanese War (1937-1945), the infamous Japanese Army Unit 731 (Japanese Army)Unit 731 conducted experiments on thousands of people in occupied China. The unit was formed and headed by General Ishii, ShirōIshii, ShirōShirō Ishii (1892-1959). Ishii started with experiments in 1932 and was given control of his own research facility in 1936. He was appointed chief of the Biological Warfare Section in 1940 and headed Japan’s bioweapons program, the largest of any nation during the war, until the end of the war. He received immunity from prosecution in 1946. During World War II, Japanese Army Unit 731 (with up to three thousand men) and other special units tested various agents on Chinese prisoners of war as well as civilians, usually disguising the tests as vaccinations or claiming that they were for medical research. Around 400,000 people are thought to have perished in these “experiments” and deliberate attacks. In October, 1940, bubonic Plagueplague was spread in the Chinese cities of Qu Xian (Chü-hsien) and Ningbo, killing twenty-one and ninety-nine people, respectively. Another attempt in November in Kinhwa did not lead to a breakout of plague. By the end of 1941, prisoners of war were infected with typhoid. AnthraxAnthrax was used in May, 1942, in retaliation for the Doolittle raid, but when the disease also spread to retreating Japanese troops, Ishii was relieved of command of Unit 731. As efforts to develop an aerosol failed, rats and insects were infested with bubonic plague and set free in cities or dropped in ceramic bombs.

Programs to weaponize diseases, including various forms of plague and anthrax, were carried out by other states as well. Such efforts continued after World War II. The United States;biological warfareU.S. program was headed by Merck, George W.Merck, George W.George W. Merck (1894-1957) and Baldwin, IraBaldwin, IraIra Baldwin (1895-1999), who became the first director of the U.S. Biological Warfare Laboratories (Maryland)Biological Warfare Laboratories in Maryland in 1943. There are allegations of bioweapons, developed under Baldwin, being used during the Korean War by the United States.

Chemical weapons are most widely associated with World War I. Germany;chemical weaponsGerman scientists developed various types of WMDs for this conflict, although the term Gas;weapons“gas war,” often applied to this war, is somewhat misleading. The chemical agents used were mostly liquids or aerosols; some of these agents would develop into a gas only over time or were delivered as a fine spray that looked like a gas. Methods of deployment varied. First, canisters with the liquids were brought up to the front and opened, facing the enemy, where it was hoped that the wind would blow the gas or aerosols toward enemy lines. In many cases, shifting winds inflicted more casualties on the side that had deployed the chemical weapons. Later, grenades were filled with the chemical agents and fired against the enemy. Upon impact, they burst apart and spread the liquids. Airplanes were also used to spray the chemical weapons over large areas.

Israeli students wear gas masks in 2003 during a drill to prepare them for the possibility of a chemical attack.

(AP/Wide World Photos)

Chlorine Chlorine gasgas was first used on April 22, 1915, by the German army at the Ypres, Second Battle of (1915)Second Battle of Ypres (1915) on the western front. The German army deployed some 5,700 cylinders north of Ypres, containing nearly 170 tons of chlorine. The gas was released, forming a gray-green cloud that drifted toward French colonial troops, who broke ranks. The Germans used gas on three more occasions during that battle. Some ninety men died immediately from gas poisoning in the trenches, more than two hundred were wounded, and sixty of them later died. As the Germans were also afraid of the effects of the gas and lacked reinforcements, the break in the front lines could not be exploited. These scenes would be replayed often during the remainder of the war. “Gas attacks” in the end had more of a psychological than a truly military effect.

Lethal in high doses, its smell and color made chlorine a relatively ineffective weapon, as it could easily be spotted. PhosgenePhosgene, more lethal and harder to detect, was later used. Both agents caused harm to the eyes and lungs of victims, leading to asphyxiation. Perhaps the most notorious chemical weapon deployed in World War I was the so-called Mustard gasmustard gas Dichloroethyl sulfide(dichloroethyl sulfide), which stuck to surfaces for hours. This weapon, a vesicant (blistering agent), attacked the eyes and lungs and functioned as a systemic poison. The use of gas masks during the war resulted in its being responsible for relatively few fatalities, but its use was feared and lethal to those unprotected, and it would later be used against poorly equipped armies in Ethiopia (1935-1936) and the Iran-Iraq War (1980-1988).

A leading scientist on the German side was Haber, FritzHaber, FritzFritz Haber (1868-1934). After research in the field of fertilizers and explosives, Haber developed chlorine gas for chemical warfare. His wife, Clara, committed Suicide;Clara Haber[Haber]suicide after she learned of the effects the weapon had in Ypres. Together with Bosch, CarlBosch, CarlCarl Bosch (1874-1940), Haber developed the Haber process, which can be used to extract nitrogen from the air to use in fertilizers under conditions of low temperature and high pressure. For this achievement he was awarded the Nobel Prize in Chemistry in 1918, despite also being the “father of the Gas War.” A Jew, Haber fled Nazi Germany in the 1930’s.

Pictures of a mangrove forest in Vietnam both before (top, in 1965) and after (in 1970) treatment with the herbicide Agent Orange.

(AP/Wide World Photos)

Most states worked on chemical weapons in the interwar period and had huge stockpiles of them ready for use by World War II (1939-1945). These ultimately were not used, as both sides feared the effects of these horrendous weapons. After the war, more powerful toxins were developed, mostly Nerve agents“nerve agents.” These compounds would cause muscle spasms, ultimately leading to failure of the respiratory or circulatory system. The compound known as VX (nerve agent)VX, tasteless and odorless, with the texture of motor oil, was one such nerve agent. When entering the body, it blocks an enzyme that triggers nerve pulses; the victim then suffers severe muscle contractions, which ultimately lead to death.

During the Vietnam War (1961-1975), the United States used various types of chemical agents, such as Agent OrangeAgent Orange–not against persons but as defoliants, to deforest the jungle areas in Southeast Asia. The detrimental effect upon animals and also people, due to its high content of Dioxindioxin, was unintended and discovered only later.

In 1988, Iraq;chemical warfareIraqi dictator Hussein, SaddamHussein, SaddamSaddam Hussein (1937-2006) used poison gas against Kurdish gassingsKurdish civilians in Halabja during the Anfal campaign. Kurdish villages were bombed by the Iraqi Air Force with multiple agents, most likely including mustard gas, and the powerful nerve toxins sarin, tabun, and possibly VX. Some five thousand civilians were killed in this incident alone. Iraq also used poison gas during the Iran-Iraq War (1980-1988)[Iran Iraq War]Iran-Iraq War. Western sources did not at first believe this and even claimed that Iran, not Iraq, had used the weapons. The United States later referenced this use and ability to manufacture such chemical weapons to make the case that Iraq still possessed WMDs.

On March 20, 1995, the Japanese Tokyo subway attack (1995)Aum ShinrikyoSarin gasAum Shinrikyo sect used sarin gas for a terror attack on the Tokyo subway system, the first modern use of a WMD by terrorists. This incident shocked the world and highlighted how vulnerable civilian populations were to chemical and biological attacks.

Today, both biological and chemical warfare are covered by conventions under the auspices of the United Nations. The 1992 Convention on the Prohibition of the Development, Production, Stockpiling, and Use of Chemical Weapons and on Their DestructionConvention on the Prohibition of the Development, Production, Stockpiling, and Use of Chemical Weapons and on Their Destruction, administered by the Organization for the Prohibition of Chemical Weapons, and the 1972 Biological Weapons Convention (1972)Biological Weapons Convention, signed by more than one hundred countries, outlaw the storage, stockpiling, and use of these weapons.Biological warfareChemical warfareDisease;as weapon[weapon]

Books and Articles
  • Barenblatt, Daniel A. Plague upon Humanity: The Secret Genocide of Axis Japan’s Germ Warfare Operation. New York: HarperCollins, 2004. Summary of the known facts about Japan’s biological warfare capability, carefully developed with the direct support of the emperor and tested in China.
  • Endicott, Stephen, and Edward Hagerman. The United States and Biological Warfare: Secrets from the Early Cold War and Korea. Bloomington: Indiana University Press, 1998. The authors present an impressive array of evidence that the military and executive branch lied to Congress and the public about the development of biological weapons and even used them in Korea.
  • Harris, Sheldon H. Factories of Death: Japanese Biological Warfare 1932-45 and the American Cover-Up. New York: Routledge, 1994. Meticulous research on Japan’s secretive experiments on live human beings and U.S. complicity in covering up the truth after World War I.
  • Jones, Simon. World War I Gas Warfare Tactics and Equipment. New York: Osprey, 2007. Explains practical details, such as the means and tactics of delivery, the effects and influence on the battles, and the race to produce better protection for the troops on both sides, of this type of warfare, which became one of the dominant aspects of World War I.
  • Mangold, Tom, and Jeff Goldberg. Plague Wars: A True Story of Biological Warfare. London: Macmillan, 1999. Covers research facilities and scientists in the former Soviet Union, the United States, and other countries.
  • Mayor, Adrienne. Greek Fire, Poison Arrows, and Scorpion Bombs: Biological and Chemical Warfare in the Ancient World. Woodstock, N.Y.: Overlook Duckworth, 2003. Shows that biological and chemical weapons saw action in battles long before the modern era.
  • Robinson, P. J., and M. Leitenberg. The Rise of CB Weapons. Vol. 1 in The Problem of Biological and Chemical Warfare. Stockholm: SIPRI, 1971. Detailed account of research and development in biological and chemical warfare worldwide and the often little-known use of biological and chemical weapons.
  • Williams, Peter, and D. Wallace. Unit 731: Japan’s Secret Biological Warfare in World War II. New York: Free Press, 1989. Explains this infamous unit and its projects in China.

Chemical and Biological Weapons

Medicine on the Battlefield

Psychological Effects of War

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