CONTINENTAL NOTES — GERMANY. 233 



conditions. The start was made in the wrong direction, and, 

 though none of the various theories promulgated could at any 

 time have stood the test of a really searching inquiry, they were 

 accepted for want of something better, and it became merely 

 a question of follow the leader. 



The merit of having effectually disturbed this condition rests 

 with Drs Albert and Zimmermann, of Eberswalde. Their 

 labour is characterised by careful, painstaking, and unprejudiced 

 research ; and the position that the root-pest attacks, almost 

 invariably, all afforestations with pine and spruce and almost all 

 other conifers, on every description of waste land, and that only 

 bona fide forest soils offer immunity against this disease, is more 

 firmly established than ever, But why this should be the case 

 is as yet an unsolved problem, for Zimmermann found, in the 

 course of his investigations, at least one instance where the 

 soil in a diseased forest grown on heather land had an entirely 

 satisfactory porosity. 



The question naturally arises, Do micro-organisms exist in 

 forest soils which protect the pine roots from this particular 

 form of disease ? Or are there others in waste lands which 

 attack the roots of certain species, or which render them liable 

 to attacks by the fungi, present as Saprophytes in all forest soils, 

 but assuming dangerous characteristics in waste-land soils? 

 This of course is pure speculation, but one fact seems to stand 

 out, and to indicate the way further inquiries might take, viz., 

 that those trees are immune from root-rot, which, in spite of 

 the vast amount of nitrogen they use up in their formation, not 

 merely maintain the original percentage of nitrates in the soil, 

 but increase it. It is self-evident that this can only be effected 

 by a direct assimilation of the inexhaustible supply of the 

 nitrogen in the air, and it has been ascertained by the Hungarian 

 scientists Zemplen and Roth, that the organs having the power 

 of absorbing nitrogen direct from the air (a power first discovered 

 by Jamieson) are more evident on broad-leaved species than 

 on conifers, and show a much more pronounced albumen reaction. 

 This, however, by no means precludes the correctness of the 

 bacterial and mycological theory- they may co-exist and supple- 

 ment each other. There is still much to learn in this respect.^ 



^ A German, fairly comprehensive, extract of the work by Dr Geza Zemplen 

 and Julius Roth, under the title " Beitraege zur Stickstoff Aufnahme des 

 Waldes," appeared in the Erdezeti Kiserletek, in Selmbanya, Hungary, and 

 is well worth studying. 



VOL. XXH. PART H. Q 



