Hostess (short story)

It was first published in the May 1951 issue of Galaxy Science Fiction and reprinted in the 1969 collection Nightfall and Other Stories and Robot Dreams.

Harg Tholan, a medical researcher from Hawkin's Planet, visits Earth to work at the Jenkins Institute for the Natural Sciences.

Tholan reveals that the other races normally live indefinitely, growing at an ever-slowing rate over time, like Earth trees.

She considers whether the disease was created on Earth as a biological weapon, but rejects it as impossible, given humans' lack of understanding of alien physiology.

Reviewing the dinner conversation, she remembers Drake's seemingly overreaction to Tholan's polite mention of what a good hostess she was.

He explains that the disease has been on Earth for millions of years, and higher animals live with it within their DNA[a] as a sort of parasite.

She notes Drake's reaction to Tholan's use of the term "hostess" and her offhand mention of mosquitos, carriers of disease.

Drake admits that they are indeed aware of the disease, but can do nothing; it now lives in a symbiotic relationship with humans, its growth-inhibiting properties preventing cancer from killing everyone.