FIELD CROPS. 545 



with tho fflnrosids aro onzynis which iict upon llic ^'hicosids, lib«>ratinK pnissic 

 acitl. 



Attoiitidii is c.ilhMl to the iMct th;il iillJc is !<no\vii rcn.-ii-diiiji liu' iiictliod iiy 

 which prussic acid is i)r<)(hiccd i).v jtlants, altlioiij,di it has been suggested tliat 

 it is roriued i)y tiie reduction of nitrates by lornialdehyde. The need of furtlier 

 investigations on this subject is pointed out. 



A study on leguminous tubercles, J. Stefan {Vciitbl. liakt. [cfc], 2. Abt., 

 16 ili)0()), .\(). .'i-(j, pp. 131-1'ii). pis. ,i. ptjs. 2). — Summarizing his investigations, 

 the author states tliat the micro-organisms causing root tubercles on legnnu- 

 nous phmts live for a (iiiic at the expense of tlie host plant, after whicli they 

 become degenerate pathological forms. This degeneration is said to be due 

 to the accumulation of injurious substances secreted by tlie organisms, and 

 extends to the cells of the host plant, ultimately involving the entire tubercle. 

 The transfer of the assimilable nitrogen from the organisms to the host plants 

 follows the ordinary pliysical laws of osmosis. On the whole the host plant 

 gains by the symbiosis as it receives all the albuminoid substances produced 

 b.v the micro-organisms and uses them in building up its tissues. 



The tubercles which appear in the axils of small rootlets branching from the 

 larger ones really have their origin from the larger rootlets. In some peren- 

 nial leguminous plants round degenerate tubercles are often found. The au- 

 thoi"'s investigations indicate that in some plants, such as Galega. the tubercles 

 serve as true storage organs. 



The infection strands of Phaseolus were found to not retain their vitality 

 very long, but they are usually as abundant as in the majority of legumes. 

 In the olovei's they are especially persistent. In nearly all kinds of infection 

 strands there are to be found numerous sudden swellings which contain the 

 so-called bacteroids. These bacteroids are involution forms which while .voung 

 are thin-walled and ciipable of rapid division, but when older become swollen 

 and finally degenerate. The bacteroids seem to be able to break through the 

 infection strands at any point. 



In considering the classification of Bacillus iddiricoUt, the author thinks 

 it should be pl.-ictnl near the ^lyxobacteriacea-. 



The influence of certain oligodynamic actions on the development and 

 activity of Bacterium radicicola, H. I'ehotti (Scpiirdtr from Ann. Ii<)t.[ Jinnic]. 

 :'i {litOC)). A'o. /. pp. S7-H2). — A series of pot experiments with beans, alfalfa, 

 and red clover was conducted in which, in addition to equal amounts of fertili- 

 zing constituents, various niuounts of a nunii)er of min(>ral compoimds were 

 added. Solutions varying from 1 i)art in no.Odd to 1 part in 'J.^ciO of the sul- 

 I)hates of potassimn. cln-omiuni, manganese, ii'on, cobalt, nickel, and cojijier. ;ind 

 of the chlorids of barium and nici-<in'y were added to the cultures and the 

 efifects on growth noted. All llic cultures showed a stinudation due to the 

 oligodynamic .-iction of the solutions. In general, there was an increase in 

 growth, dry weight, number and weight of tuiu'rcles, etc., corresponding to the 

 increase in the atomic weight of the minenil uj) to a certain point, after which 

 there was a falling off in a corresi)omling ratio. 



FIELD CROPS. 



Guide to plant culture, M. Fischer {Lcitfuden <ler Pflansenhaulehre.—Stutt- 

 (jart: E. rimer. JlXiG. pp. 2-il, fl(j,s. lid). — This book is intended for the practical 

 farmer and for use in agricultural schools. It is divided into ') parts, the first 

 treating of jilant culture in general and including i)lant nutrition, soil, and 

 climate; the .second part being devoted to s|)ecial i)lant culture, with discus-' 

 sions on the growth of cereals, leguminous croi)s, forage plants, hoed crops, and 

 industrial crops ; and the third part discussing jilant breeding in its general 



