Virus was recovered from eye swabs, throat swabs and urine (but not from feces) for six months after inoculating Swiss-Webster mice subcutaneously or intraperitoneally. The lacrimal gland, salivary gland and kidney were the apparent sources of excreted virus. Serum complement-fixing antibody titers were greater and persisted longer than neutralizing antibody. The quantity of virus with which animals were inoculated was positively correlated with both the extent of viral multiplication in the salivary gland and the complement-fixing antibody titer. Methotrexate suppressed the antibody response and increased the extent of viral multiplication if given before and during acute infection, but it did not alter the characteristics of chronic infection.