When mice were treated with 1–25 mg cortisone acetate thrice weekly, recovery of Hymenolepis murissylvaticae was significantly higher than in untreated controls, both in oral infections with six cysticercoids and surgical transplantations of one 7-day or 8-day-old worm. Cortisone treatment also resulted in the worms being located more anteriorly in the small intestine.Evidence of an immunological response against the tapeworm in the intestine is given by: (a) an accelerated rejection of a secondary oral cysticercoid infection and a significant difference of the dry weights of the worms recovered on day 10 in CFLP mice; (b) an accelerated rejection of a secondary surgical infection on days 4 and 6 in CFLP mice and on days 3 and 4 in NMRI mice; (c) an accelerated rejection of a secondary surgical infection given 3 and 6 months after the primary immunizing infection in SWlSS-albino mice.
