1. By inoculating the scarified surface of both sides of the scrotum of rabbits with suspensions of Treponema pallidum, 100 per cent of infections were obtained on one side or the other. Infection through the unbroken skin could not be produced.
2. By gland transfers from animals with positive local inoculations, 87.5 per cent of takes were produced.
3. These two methods were used to test the prophylactic value of 30 per cent calomel ointment, (a) Calomel ointment proved efficacious up to 8 hours after inoculation with syphilis, (b) No marked difference appeared between the action of calomel in a base of lanolin and vaseline and in a base of benzoinated lard and wax. (c) Death from mercurial poisoning was produced in rabbits by a single application of a large amount of calomel ointment.
4. The method of gland transfers was used to test the sterilizing effect of arsphenamine and neoarsphenamine on old infections in the rabbit. The infection was completely abolished in every instance, whether by one, two, or four intravenous doses.
5. Natural spirochetosis of rabbits need not be a serious complicating factor in work on syphilis in rabbits, for the following reasons. (a) In natural spirochetosis, the lesions occur on the penis and not on the scrotum. Gland transfers are negative, (b) A scrotal lesion can be produced by inoculation, but it can be distinguished from that of Treponema pallidum infection by its course, (c) In studies of generalized syphilis supposed to involve the genitalia, and in sexual transmission experiments, Treponema cuniculi may be a serious complicating factor.