The buff coagulum is cut into small pieces, about 1 c.c. in volume. They must be forced with a sterile glass rod to the bottom of the semi-coagulated serum and saline mixture. The medium is inoculated with a small quantity of infected blood and kept at 37° C. In the case of S. recurrentis, growth of spirochætes is observed on the second day, reaching a maximum in five to seven days. The growth of the organisms proceeds rather more slowly, they live for a longer period and maintain their virulence better than in Noguchi’s medium.
Treponema pertenue, Castellani, 1905.
Syn.: Spirochæta pertenuis; S. pallidula, Castellani, 1905.
Castellani discovered the organism in 1905, in scrapings of yaws pustules. He first described it under the name of Spirochæta pertenuis.
Fig. 58.—Treponema pertenue. (After Castellani and Chalmers.)
Treponema pertenue (fig. 58), though delicate and slender, shows great morphological variation both in length and thickness. It may be short, e.g., 7 µ, but can attain 18 µ to 20 µ in length and may be even larger. In cultures made by Noguchi, thick, medium and thin forms were found, each giving rise to a different type of frambœsial lesion when inoculated into the testicles of rabbits, thus suggesting the possibility of the occurrence of varieties of T. pertenue.
The organism is difficult to stain, but occasionally deeper staining granules are found along its body. They may represent a diffuse nucleus. Granule formation similar to that of T. pallidum has been observed by Ranken, using dark-ground illumination.