Tsetse
2 of the 6 encyclopedias on this shelf carry an entry for Tsetse. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
tset'se, a South African fly. It is a trifle larger than a house fly. It is brown in color and has four yellow bars across the abdomen. It has somewhat the appearance of a small brown horsefly. It it a terrible pest. Its bite has long been considered fatal to the horse, ox, and dog. Livingstone, the African explorer, lost forty-three oxen in a single trip. As a matter of fact, it has been ascertained that the fly is merely a carrier of disease. Like the malaria-carrying mosquito, it sucks up infection when stinging a diseased animal and introduces the germs when stinging a healthy animal. Its bite has no effect on man, or mules, or on the native wild animals. The difficulty of cultivating fields where oxen and horses cannot be depended upon, and the impossibility of grazing cattle in certain regions, has retarded the settlement of South Africa. There are seven species of the fly. Only one carries the blood parasite. See Fly ; Mosquito
Collier's New Encyclopedia (1921)
the native name of Glossina morsitans, a dipterous insect, slightly larger than the house fly, from Africa, ranging from 18°-24° S. latitude. It is brown, with four yellow transverse bars the abdomen, beyond which the on wings project considerably. The head is armed with a proboscis adapted for piercing the skin, and the fly lives by sucking TSETSE FLY blood. At first no effect is perceived, but in a few days after an ox has been bitten, the eyes and nose begin to run, the coat bristles, a swelling appears under the jaw, and sometimes at the navel, emaciation and flaccidity of the muscles ensue, followed by purging, staggering, in some cases madness, and finally death. On dissection the cellular tissue under the skin is found to be injected with air, as if a quantity of soap bubbles were scattered over it. See SLEEPING SICK NESS.
What Has Changed in the Last Century
Aiton's 1910 entry states flatly that the tsetse's "bite has no effect on man" and that only one of seven species carries the blood parasite; Collier's, eleven years later, already cross-references its own article on sleeping sickness. The human link had in fact been nailed down in 1903, when David Bruce and colleagues in Uganda showed that Glossina transmits the trypanosome of sleeping sickness, and cattle nagana is likewise caused by trypanosomes rather than any venom. Modern taxonomy recognises roughly thirty species of Glossina spread across some three dozen sub-Saharan countries, most of them capable of carrying trypanosomes, and the "soap bubble" appearance Collier's describes on dissection is no longer part of how the disease is diagnosed. Control has moved from shooting out game to insecticide-treated targets and the sterile-insect technique, which wiped the fly off Zanzibar in the 1990s; reported human sleeping sickness cases have fallen from tens of thousands a year in the 1990s to under a thousand, and the World Health Organization now treats elimination as a realistic goal.
Written for this edition, 2026.