The present work deals with the so-called experimental mumps. The virus employed in the present work is the amniotic virus of Showa B strain, which was isolated by the present authors from a case in the epidemic of February in 1952 by the intra-amniotic inoculation of pure parotid saliva of the case. At the time of the present experiments, the hemagglutination titre of the virus was 1280, and was bacteriologically proved to contain no organisms. The virus was introduced into the volunteers in the amount of 0.2-0.3 cc through the Stensen's duct by Johnson and Goodpasture's technique unilaterally. The ager of the volunteers ranged from 8 to 20 years. Although their pre-experimental history was unknown, their clinical signs in various fields and blood hemograms were investigated before and after the experiments. Specimens of blood were taken from them for the immunological investigations which will be described later. The concentrations of the virus given were undiluted amniotic fluid, and 1: 5 and 1: 100 diluted amniotic fluids, though the concentration was found unrelated to the manifestation of the disease.
Among the 10 cases where active virus was given, 2 cases demonstrated the ordinary incubation period of approximately 20 days, though 3 cases of the remainders showed in-cubation periods ranging from 1 to 3 days accompanied by eminent relative lymphocytosis and swelling of the parotid gland in parallel with the incubation period. The prognosis was quite favorable. The side of the smollen parotid gland coincided with that of the inoculation. In 5 cases of the volunteers, no signs what-so-ever were recognized, but antibydy formation was slightly proved in 3 cases among them by the immunological in-vestigations, which will be dealt with later. No cases of the volunteers inoculated with the virus inactivated by ultraviolet irradiation manifested any clinical sign. Further, no complement fixing antibody was proved among them.
In the present work, in short, the mumps with unilateral swelling of parotid gland induced by the inoculation with this virus was successfully proved clinically.
