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Science  23 Mar 1945:
Vol. 101, Issue 2621, pp. 311-312
DOI: 10.1126/science.101.2621.311


In this preliminary note we describe the results obtained by inoculation of the skin of the scrotum of four black rabbits with serous fluid expressed from an initial pinta lesion. The inoculation was made intradermally, as superficially as possible, with serous fluid rich in treponemata and diluted with normal salt solution. A papule appeared at the point of inoculation in one of the four rabbits on the 105th day. One hundred and fifteen days after inoculation the papule presented a circular erosion on an indurated base. The serous fluid expressed from this lesion contained numerous treponemata on dark-field examination, and these were easily impregnated by the Fontana-Tribondeau method. A volunteer inoculated with serous fluid expressed from the rabbit's lesion developed a typical initial pinta lesion at the point of inoculation, thus proving that the scrotal lesion of the rabbit was produced by Treponema carateum or Treponema herrejoni, the causal agent of pinta, mal del pinto or carate.

Four rabbits inoculated with serous fluid from the scrotal lesion of the rabbit have not yet developed visible lesions.