RESUMO
A technique is described for the intratesticular inoculation in mice and rats of suspensions of M. leprae murium, and for subsequent quantitative assessment of bacterial multiplication by counting the numbers of stained bacilli in homogenates of testes from animals killed at inervals. The method is convenient to carry out, and a statistical assessment shows that considerable accuracy is attainable. Bacilli from an 18-month-old rat leproma, transferred to a different host species, the mouse, showed a "lag" phase of 2-5 weeks in its multiplication, succeeded by a logarithmic phase which ciontinued for a further 2-3 months. On the other hand, when rat testes were inoculated with bacilli from a 7-month-old rat-testis leproma, the logarithmic phase was entered at once. The mean generation time in this phase was 7-8 days in rats, and 10 days in mice. During the "lag" phase a transient but significant increase in average bacillus length occurred. Suramin treatment of mice enhanced the growth of the bacilli in them. In rats, however, its effect was to decrease the rate of multiplication.