This was a graph used in an article in the 1937 issue of Archives of Internal Medicine, volume 59, pages 967-980. The article was authored by, K. F. MEYER, M.D., Ph.D.; C. L. CONNOR, M.D.; F. S. SMYTH, M.D.; et al., and was entitled, “Chronic Relapsing Latent Meningeal Plague”. The graph highlighted the clinical record of a patient referred to as C.P., a 10-year-old boy, who had resided in Tulare County, California, and had contracted a case of bubonic plague, caused by the bacterium, Yersinia pestis, formerly known as Pasteurella pestis.