Observations on the Blood Cytology in Experi- Mental Syphilis I. Th~ P~.iod of Disease Activity By

Among the outstanding features of the blood picture in experimental syphilis of the rabbit, Pearce (1) has reported the following: A slight increase in the total white count; unchanged or lowered lymphocyte values during the earlier phase of the disease, with increased values during the period of regression and healing of lesions; and a marked increase in the number of monocytes during the period of disease activity. These findings were presented in terms of percentage deviation from preinoculation mean values, and the results, which were considered from the standpoint of the clinical course of the disease, were charted with particular reference to the time in weeks after inoculation. With these observations as a background, and in connection with our investigations of various aspects of host reactions to environmental influences, including disease conditions, the study of the blood of syph-ilitic rabbits was continued. Special attention was again paid to the cytological levels during the active phase of the disease as compared with preinoculation values, while additional comparisons were made with the findings in normal rabbits during the same period. Furthermore, observations were also made in the period of latency when all clinical manifestations of the disease have healed and the animal appears to be "normal." The results of this study are reported in this and the subsequent paper (2). In the latter paper (2), a comparison is made between the cytological findings in experimental and human syphilis (3).