REVIEWS 115 



In co-operation with this latter city, the State forester liopes to make 

 revenue from the management of these reserves. 



Planting will be necessary on these watersheds, in which the State 

 nursery, established in 1914, may serve, from which applicants can 

 secure material at cost. As the charge made for this stock is in the 

 neighborhood of $7 per thousand — the list for various stocks varying 

 from $4 to $18 — it seems a questionable advantage. We see that black 

 locust and catalpa have played an undeserved role in previous distribu- 

 tions. The State itself has planted 475 acres. Although there is a 

 State protective organization of 148 forest wardens (without salary), 

 the damage from fire during the last five years averaged over $100,000. 

 "The system of fire protection in operation is as effective as it is pos- 

 sible to make it without increased appropriation." 



Attention is given to insect and fungotis diseases ; among the latter 

 the chestnut blight has been in the State since 1910 and has caused con- 

 siderable damage. 



B. E. F. 



Studicr over salpeterhildningen i naturliga jordmdner och dcss hety- 

 delse i vdxtekologiskt avseende. Skogsvardsforeningens Tidskrift, 

 April- June, 19 17. Pp. 321-446. 



Notable advances have been made in recent years in the investigation 

 of the composition of soils and the formation of humus. Among these 

 researches may be mentioned the work of Suzuki (1906-08), who by 

 means of the ester method devised by Emil Fischer has succeeded in iso- 

 lating from natural humus a number of monoamino and diamino acids, 

 presumably decomposition products of albuminous substances found 

 in the soil. Robinson (1911) has succeeded in isolating from peat such 

 compounds as leucine and iso-leucine. Much has been accomplished 

 by Schreiner and his associates in the United States Bureau of Soils, 

 who have isolated the following compounds from soils containing small 

 amounts of humus : Xanthine, hypoxanthine. adenine, arginine. lysine, 

 histidine, koline, trimethylamine, and also non-nitrogenous compounds, 

 among which are phytosterine, agrosterine, oxalic acid, mannitol, and 

 rhamnose. Schreiner has even found it possible to isolate from such 

 soils certain organic compounds that arc toxic to higher plants, as, for 

 instance, dihydrooxy-stearic acid. 



Important as these American researches arc. Hesselman cautions his ' 

 readers that their value must not be overestimated. With the excep- 

 tion of Robinson's studies on peat, they deal only with light-colored 



