"In Hancock County, Ill., oaks have been succeeded by hickories." "In East Hamburgh, Erie County, N.Y., a growth of hemlock, elm, and soft maple, was succeeded by beech, soft maple, and hard maple, but a good deal more of the last named than any other." This is the general character of the summary given, and if its object were simply to show the fact that these alternations actually took place (one that nobody has disputed in the last half century), his chapter on the "Alternations of Forest Growths," is a scientific success. The information really desired in these cases, was that imparted by Dr. Dwight in his suggestive work of travel, in which all the incidental facts and surrounding circumstances are fully given. It does not appear from any of the foregoing statements, given as a specimen, that there were any neighboring trees sufficiently near to have supplied seed for the new forests taking the place of the old,--manifestly the most important physiological fact connected with the whole inquiry, whether looking to proper forest-management, or to future "schools of forestry," certain to be established in this country, as they have been in most of the leading countries of Europe. It is, however, stated by Dr. Hough, in his voluminous report, that, "in New England, the pine (without giving its varieties) is often succeeded by the white birch, and, in New Jersey, by the oak; the succession of oak by pine, and the reverse, in the southern states." And it is further stated, without reference to the nature and quality of the different soils, or the absence or presence of neighboring seed-trees, that "poplars and other soft woods are very often found coming up in pine districts that have been ravaged by fire." "We have noticed," he continues, "in Nebraska, ash, elm, and box-elder following cottonwood. In the natural starting of timber in the prairie region of Illinois, where the stopping of fires allowed, we often see a hazel coppice; after a time the cratægus, and finally the oaks, black-walnuts, and other timber. These growths are often quite aggressive on the prairies. In Florida, the black-jack oak usually takes the place of the long-leaf pine." In all these cases, the contiguousness of similar, or dissimilar growths, is not stated.