1917] DISEASES OF PLANTS. 245 



of trees recommended for various planting purposes in Idaho, including a price 

 list of trees which the department of forestry of the station is prepared to fur- 

 nish the residents of the State. 



The status and value of farm woodlots in the eastern United States, E. H. 

 Frothingham (V. S. Dept. Agr. Bui. 481 (1917), pp. 43, pi. 1, figs. 2).— The pur- 

 pose of this bulletin is to show as nearly as can be done from available census 

 statistics what the relation of the woodlot has been to the agricultural develop- 

 ment of different parts of the East, what the tendencies appear to be, and, in 

 general, what value the woodlot actually has to the Nation, the rural com- 

 munity, and the individual farm. The subject matter is presented under the 

 general headings of woodlots of the Eastern States, how the growth of farming 

 has affected the woodlot, amount and quality of woodlot timber, what the wood- 

 lot promises for the future, and the woodlot as a farm resource. In addition 

 to considerable tabular data maps are given showing the proportion of wood- 

 land to total farm land in different sections of the East and the actual farm 

 woodland area in the United States in 1910 by counties. 



Canadian woods for structural timbers, H. N. Lee (Dept. Int. Canada, For- 

 estry Branch Bui. 59 (1917), pp. 44, figs. 22).— This bulletin gives a sketch of 

 the forest resources of Canada and discusses the qualities that affect the use- 

 fulness of timber for structural purposes. Descriptions are then given of the 

 chief Canadian species suitable for this purpose and comparisons, tables, and 

 charts relating to mechanical and physical tests. The bulletin concludes with 

 a short discussion of the grading of timber. 



Forest products of Canada, 1913, 1914, and 1915, R. G. Lewis et al. 

 (Dept. Int. Canada, Forestry Branch Buls. 52 (1915), pp. 79, pis. 2, figs. 5; 57 

 (1916), pp. S2, pis. S, figs. 7; 58 (1917), pp. 72, pi. 1, figs. S).— These comprise 

 statistical reports for the years 1913, 1914, and 1915, respectively, relative to the 

 use of lumber, lath and shingles, pulpvs'ood, poles, and crossties throughout the 

 Dominion. The production is given both by Provinces and by kinds of wood. 



The recent industrial and economic development of Indian forest products, 

 R. S. Pearson (Jour. Roy. Sac. Arts, 65 (1917), No. SS66, pp. 487-493).— A paper 

 on this subject read before the Indian section of the Royal Society of Arts in 

 April, 1917. 



DISEASES OF PLANTS. 



The susceptibility of cultivated plants to diseases and pests, P. B. Keu- 

 CHENius (Teysmannia, 27 (1916), No. 1-2, pp. 65-77). — This is a somewhat 

 general discussion, with illustrative examples, of the several degrees of para- 

 sitism of economic plants, namely, infections induced by weakness, injury, or 

 true parasitic activity of the attacking organism with the circumstances favor- 

 able thereto, as virulence, stage of development of host or parasite, physical 

 conditions, and specializations. 



Studies in the physiology of parasitism, W. Brown (Jour. Bd. Agr. [Lon- 

 don^, 23 (1916), No. 5, pp. 474-478).— This is a summary of work done and re- 

 sults obtained by the author and by Blackman and Welsford as previously 

 noted (E. S. R., 37, p. 47). 



A study of Gloeosporium, KrIJgee (Mitt. K. Biol. Anst. Land u. Forstic, No. 

 15 (1914), pp. 15, 16). — A brief review is given of a few species (with their 

 hosts) of Gloeosporium, of which CoUetotrichum is treated as a subgenus. 



Further evidence as to the relation between crown gall and cancer, E. F. 

 Smith (Proc. Nat. Acad. Sci., 2 (1916), No. 8, pp. 44.^-448).— Previous opinions 

 are reviewed regarding cancer in animals and crown gall in plants. The 

 author states that if inoculations with Bacterium tumefaciens are made in 



