The idea of probit analysis was originally published in Science by Chester Ittner Bliss (1899–1979) in 1934. He was primarily concerned with finding an effective pesticide to control insects that fed on grape leaves. By plotting the response of the insects to various concentrations of pesticides, he could visually see that each pesticide affected the insects at different concentrations, but he didn’t have a statistically method to compare this difference. The most logical approach would be to fit a regression of the response versus the concentration, or dose and compare between the different pesticides.