TABLE 3 .

Retention of infectivity by in vitro-cultured T. pallidum Nichols

T. pallidum dosage per site	No. of lesions/ no. of sites inoculated	Day of lesion development	Avg day of lesion development
Experiment A: inoculum = 45-day culture
460,000	4/4	7, 7, 7, 7	7.0
100,000	4/4	8, 8, 8, 8	8.0
10,000	4/4	9, 11, 11, 11	10.5
100	3/4	18, 19, 20	19.0
10	2/4	21, 26	23.5
Experiment B: inoculum = 116-day culture
10,000	6/6	11, 11, 11, 11, 11, 12	11.2
1,000	6/6	11, 11, 11, 11, 11, 12	11.2
100	6/6	14, 16, 16, 17, 17, 18	16.3
10	6/6	23, 24, 24, 25, 29, 29	25.7
1	3/6	19, 36, 36	30.3