The Hogben test used the frog's sensitivity to human chorionic gonadotropin. A sample of a woman's urine was injected under the skin of a female Xenopus laevis, and if hCG was present the frog ovulated and released eggs within roughly eight to twelve hours. The test was accurate, quick by the standards of the time, and it did not kill the animal, unlike the earlier mouse and rabbit tests that required dissection.
The method was used widely from the late 1930s until immunoassays displaced it in the 1960s. Colonies of Xenopus were maintained in hospital basements across Europe, North America and southern Africa, and the same trick still serves laboratories: injecting hCG remains the standard way to induce Xenopus to lay eggs for developmental biology.
The global trade left a legacy. Xenopus laevis carries the amphibian chytrid fungus while often surviving infection, and the international movement of laboratory and escaped frogs is one of the hypothesised routes by which chytridiomycosis spread. Feral populations are established in the United States, Chile, Europe and Japan.