text: The first use of a bioassay dates back to the late 19th century, when the foundation of bioassays was laid down by German physician Paul Ehrlich. He introduced the concept of standardization by the reactions of living matter. His bioassay on diphtheria antitoxin was the first bioassay to receive recognition. His use of bioassay was able to discover that administration of gradually increasing dose of diphtheria in animals stimulated production of antiserum.
  One well known example of a bioassay is the "canary in the coal mine" experiment. To provide advance warning of dangerous levels of methane in the air, miners would take methane-sensitive canaries into coal mines. If the canary died due to a build-up of methane, the miners would leave the area as quickly as possible.
  Many early examples of bioassays used animals to test the  carcinogenicity of chemicals. In 1915, Yamaigiwa Katsusaburo and Koichi Ichikawa tested the carcinogenicity of coal tar using the inner surface of rabbit's ears.
  From the 1940s to the 1960s, animal bioassays were primarily used to test the toxicity and safety of drugs, food additives, and pesticides.
  Beginning in the late 1960s and 1970s, reliance on bioassays increased as public concern for occupational and environmental hazards increased.