Excerpt from American Journal of Syphilis, Gonorrhea and Venereal Diseases, 1921, Vol. 5 In rabbits, latency is a regular phenomenon of the infection. The primary lesions develop and heal spontaneously within a period varying from a few weeks to more than a year and if lesions occur elsewhere, they pursue the same course. Within a few months from the time of inocculation, therefore, no manifestations of infection may be found. This phenomenon has been spoken of as spontaneous recovery and is generally regarded as such since very few cases of relapse have been reported. Relapses do occur, however, and while no estimation of their frequency can be given, they are more or less proportionate to the length and carefulness of the observation of infected animals. Spontaneous recovery in the rabbit is frequently only temporary and lesions of some kind may recur after the lapse of a few months and occasionally a year or more may intervene. During such intervals as these, the most careful examination fails to reveal the presence of a syphilitic lesion, either clinically or pathologically. These are cases of true latency or cases in which the animal, although still infected, has acquired some power of restraint upon the growth and multiplication of spirochetes and protection, for the time being, against their harmful effects. If relapse occurs, we know that the animal was still infected but otherwise there is but one condition to indicate that infection may still exist and this is the presence of some degree of abnormality of the superficial lymph nodes, especially the popliteals. The changes noted in cases of latent infection vary from a shotty induration of small nodes to a moderate enlargement with some degree of induration. This observation taken in connection with previous work on lymph node involvement during various stages of active infection led us to undertake a small series of experiments which had two objects in view, namely, the demonstration of infection following so-called spontaneous recovery or during periods of latency, as the case might be, and the determination of the location of the spirochetes during such periods. The apparent abnormality of the popliteal nodes and the fact that in the active stages of infection, spirochetes were always demonstrable in these nodes by animal inoculation, suggested that the simplest method of approach to this problem was by excision of popliteal nodes and the inoculation of test animals according to methods described in a previous paper. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.