Report of the unsuccessful cultivation of rabies fixed virus in a cell-free medium consisting of steamed sheep-brain extract, glycine, peptone and a number of accessory factors (tryptophan, aneurine, nicotinic acid amide, pyridoxine hydrochloride, sodium pantothenate and lactoflavin). After 24 and 48 hour's incubation at 37° C, under aerobic conditions, the virus had completely lost its virulence, and did not induce immunity to reinoculation with active virus.