The microneutralization technique and pN method of analysis were used to differentiate antibodies to Herpesvirus hominis (HVH) types 1 and 2 in the rabbit. On the basis of this and other studies, pN difference values (type 1 – type 2) higher than +0.5 were considered to represent a type 1 response, values less than +0.05 a type 2 response and values between +0.05 and +0.5 an intermediate response. In experiments in which rabbits were inoculated with one HVH type followed by injections of the other type, it appears that the intermediate response represents exposure to both HVH types. Ocular inoculation of animals previously infected with one or the other HVH type resulted in infection of the cornea in some cases despite the presence of systemic antibodies.