In an experience with smallpox limited to the town of Colorado and occurring between the dates of April 7 and May 20, 1907, the following conditions were encountered. They are interesting as confirming previous observations as to the coincidence of variola and vaccinia.
There were in all six cases of smallpox, five of which presented the coincidence above referred to. The sixth case was mild smallpox unmodified by vaccination and irrelevant to this report.
The patient in the first case was isolated as soon as the disease was determined and some eleven people who had been exposed were segregated in a detention camp and vaccinated. After three or four days in every instance the typical sore developed. Within twelve days after exposure to smallpox, and with a well-defined vaccination sore, five of the segregated persons presented the papular rash of smallpox, which rapidly proceeded to the vesicular and pustular stages.