Charles A. R. Campbell, doctor, was born in 1865 in San Antonio. He acquired his early education there, received a medical degree from Tulane University, and returned to San Antonio, where he practiced for many years. He was president of the San Antonio Academy of Medicine at one time. After becoming interested in the extermination of fever-carrying mosquitoes, he discovered that the bat was a foe of the mosquito and constructed large roosts in which bats could feed, sleep, and deposit guano, which attracted mosquitoes. In this manner Campbell attempted to eradicate the insect in large numbers and reduce the incidence of disease. He also benefited financially from the sale of guano. Campbell published his findings in Bats, Mosquitoes, and Dollars (1925), which was lauded by such notable naturalists as Theodore Roosevelt, Lord Rothschild, and Ernest Thompson Seton. Later studies, however, have found that only certain species of bats eat mosquitoes in appreciable numbers, and that bats are not as significant a factor in mosquito control as Campbell suggested. Campbell was married to Ida Hoyer, and they had one son. Campbell died on February 22, 1931.