The geographic range of poliomyelitis, as I know it, includes England, beginning in 1838, Norway, Sweden, Denmark, Germany, and on this side of the Atlantic ranging from Cuba to northern Alaska. In the last twenty-two years, several epidemics have appeared in different sections of the United States.
The first to occur in Pennsylvania was in 1907, when 131 cases were reported by the grace of the physicians, the disease not being as yet reportable. Seven counties (Elk, Forest, Jefferson, Clarion, Venango, Warren and Lawrence) shared in this outbreak. The next year there was a similar outbreak, but altogether limited to Adams County, which had been untouched the year before. Here, as later, the mapping of the cases shows that the disease is not more likely to reappear in a center previously infected than it is to appear in some new center.
In 1909 our commonwealth suffered but slightly from poliomyelitis.