212 THE NATURE-STUDY REVIEW 



[3 :7— OCT., 1907 



soil could be transmitted to its aqueous extract, independent of the salt 

 content. In later publications from the same bureau, evidence was pre- 

 sented in favor of the idea that certain poor soils contained toxic substance 

 which act to retard the growth of roots. Further evidence favored the con- 

 clusion that wheat roots %v^q. substances toxic to themselves, and that 

 this toxicity, as well as that of the soils mentioned above, can be removed 

 from nutrient solutions or soil extracts by the absorbent action of carbon 

 black, ferric hydrate, and other finely divided inert solids. 



Two recent bulletins (Nos. 36 and 40) from the Bureau of Soils have 

 contributed more information on this subject. In Bulletin 36, Living- 

 ston and others give more evidence in favor of the existence of toxic 

 bodies in unproductive soils and add certain points as to the nature and 

 origin of such substances. The conclusion is that toxic material is present 

 in certain unproductive soils, either in very minute quantities or in a very 

 slightly soluble form; that this material is volatile in some cases and in 

 others non-volatile; that it is often destroyed by boiling the soil extract 

 in which it occurs ; that it is often accompanied by an acid reaction of the 

 extract, but that in such cases the toxicity is not due to the acidity as 

 such ; that it is probably organic in its nature ; and that it is absorbed by 

 finely divided solids. As to the origin of such material, it is shown that 

 toxic properties appear not only in nutrient solutions in which wheat is 

 growing, but also in pure sand when this is used as a medium for growth. 

 Similar substances appear to diffuse from soaking wheat seeds, and a 

 similar toxicity is exhibited by the washings from the leaves and bark of 

 certain trees. 



The importance of all this to scientific agriculture is evident, and the 

 changes that these considerations may bring about in the theory of soil 

 fertility may be very profound. The beneficial effects of crop rotation 

 may be explained equally well from the standpoint of the Liebig theory 

 or of this newer one. [Plant World.] 



Primary Nature-Study. A series of excellent lesson-plans and sugges- 

 tions for first and second grades of the New York State Syllabus of Nature- 

 Study is given in the "Home Nature-Study Course," (Cornell University) 

 Vol. Ill, No. I and No. 2. Mrs. Comstock and Mr. Spencer are the 

 authors. 



Minnesota Leaflets. Some interesting nature-study leaflets for local use 

 in schools, home study and correspondence are being edited by Florence 

 E. Lillie, Minneapolis, Minn. 



Sportsmen as Game Savers. The following interesting notes are from a 

 recent letter by Dr. W. T. Hornaday to the editor of the New York 

 Times. 



Of all the gam.e laws throughout the world that are in effect to-day, at 

 least nine-tenths of them owe their existence to the initiative, the hard 

 work, and the money expenditures of sportsmen. But for the work of 

 American sportsmen in protecting wild life from the pot hunter, the market 

 hunter, and the game butcher, there would hardly be a game bird or a 

 game mammal left alive today in the United States. In this country there 

 are at least 400 permanent organizations of sportsmen, formed chiefly for 



