Workers in the Bureau of Plant Industry, Washington, D. C., have been studying the blight since 1908. In the Spring of 1911, a bill creating the commission for the investigation and control of the blight in Pennsylvania was passed, and the active work began in August 1911. The method upon which the Commission is working is outlined in Farmers' Bulletin No. 467, of the Department of Agriculture, and consists briefly of determining the area of blight infection and in removing diseased trees west of a certain line, with the purpose of preventing the western spread of the blight. This Commission has ascertained as accurately as possible the amount of infection in the various parts of the state and the results are given in a map on display here. The state is divided into two districts by a line drawn along the western edge of Susquehanna, Wyoming, Columbia, Union, Snyder, Juniata and Franklin Counties, which is approximately the western line of serious blight infection. West of this line a large portion of the state has been scouted, and the remainder will be finished early in 1913. We have learned by experience that in the winter, after the fall of the leaves, the best scouting work can be done. Persistent leaves and cankers along the trunk are readily seen, and more and better work can be accomplished than in the summer, except when the snow is very deep. Blight infections have been found in counties adjacent to this line: also in Fayette County, near Connellsville, in Warren County, near Warren, and in Elk County, near St. Mary's. These three infections were directly traceable to infected nursery stock, and in one case the blight had spread to adjacent trees. A large area of diseased chestnut in Somerset County illustrates the harm done by shipping infected nursery stock. The centre of this infection is a chestnut orchard where about 100 scions from an infected eastern orchard were grafted to native sprouts in 1908. The percentage of infected trees in the orchard from which the scions were obtained, according to a count made this Fall, averages 80 per cent. Evidently these scions brought the disease into this region, for the grafts have all been killed by the blight and every tree in the orchard is killed or infected by disease. On adjoining tracts over 5,400 infected trees have been cut, and there are a number of others in process of removal, radiating in all directions from the orchard as a center to a distance of three miles. Another infection of 143 trees was found in Elk County. It is thought that three trees at the centre of infection were diseased in 1909, although it is possible that one of these trees was already infected in 1908. In 1910, 27 additional trees were infected; in 1911, 50 additional trees, and in 1912, 228 additional trees. The disease spread in all directions from the center of infection to a distance of 700 feet. These infections are interesting in showing the rate at which the blight may travel in healthy timber.