The main incentive urged by the earlier advocates of state supervision was the fear of a timber famine. This argument vanished, however, with the development of railroads, and was then supplanted by the argument of the protective functions of the forest, a classification into supply forests and protective forests suggesting differences of treatment. Nevertheless, the belief that absolute freedom of property rights in the forest is not in harmony with good political economy--a belief correct because of the long time element involved--still largely prevails. The difficulty, however, of supervising private ownership, and the advantages of state ownership find definite expression in the policy which Prussia especially is now following, in acquiring gradually the mismanaged private woodlands and impoverished farm areas for reforestation, making annual appropriations to this end. Many other states also are beginning to see the propriety of this movement. On the whole the systematic study of the economics of forestry has been rather neglected by foresters, although the subject was discussed by early writers, _Meyer_, _Laurop_, _Pfeil_, and in modern times by _R. Weber_, _Lehr_ and _Schwappach_ (“Forstpolitik,” 1894). The latest comprehensive volume on this subject comes from _Endres_ (1905). 9. _Means of Advancing Forestry Science._ During the century, the means of increasing knowledge in forestry matters have grown in all directions; schools, associations, journals and prolific literature attesting the complete establishment of the profession and practice. * * * * *