AGRICULTURAL BOTANY. 625 



rial 1() pcM'ciMitagos tliorc is shown to be at least ."><) per cent increase in the total 

 nitrof^en in the i)lants jxrown under the blue glass. 



The author elainis that these experiments, as well as those previously reported, 

 sliow that the radiations at the right of the siieetruni assist very materially in 

 the translocation of nitrogenous materials, particularly the gluten in the wheat 

 grain during the time of its ripening. They also favor the formation of albumi- 

 noids, and it is claimed that their physiological action is no less imi»ortant tliau 

 that of those at the other extremity. 



Toxic limits and stimulation effects of some salts and poisons on wheat, 

 U. H. Jk.n.skn (Mot. (laz., .'/.? (l!)(n),\o. 1. t>i>. 1t-'i'h Pu^-S'i). — The present work 

 was undertaken for the jmrpose of ascertaining the toxic limit for wheat plants 

 in both solutions and soil cultures. The wheat seeds were germinated in sphag- 

 num and in cpiartz and transplanted to water cultures or to parafllned wire 

 l)askets containing ground quartz, after which they were supplied with culture 

 solutions containing different strengths of copper sulphate, lead nitrate, silver 

 nitrate, zinc sulphate, iron nitrate, iron chlorid, nickel nitrate, phenol, and 

 alcohol. 



The responses to the toxic salts are said to be of two kinds, acceleration and a 

 retardation of growth which progresses as the concentration increases until the 

 death point is reached. 



The author compared the effect of the different substances tested on the total 

 transpiration from each pot or culture, the average length of the sprout, the 

 green weight and the dry weight of the plants. 



The different series of investigations are reported at length, and in conclusion 

 the author points out that while considerable work has been done on toxicity, 

 none has shown the definite effects of a poison in pure soil. Such experiments 

 as have been made with garden loam are unreliable because of the multiplicity 

 of inorganic and organic substances with wiiich the introduced poison may 

 react. The author's investigations have shown that the introduction of pure 

 quartz Hour into a toxic solution, in such proportion as to form an ordinary 

 moist soil, reduces the toxicity of the solution in a marked degree. Whether this 

 is due to absorption, to a reduced freedom of movement of the soil particles, or 

 to some chemical changes is yet to be determined. 



Of the poisons tested all gave stimulating results in quartz, and all !)ut zinc 

 and copper sulphates in the solution cultures. It is thought probable that in 

 proper concentration these 2 might also be found stimulating. 



The more dilute Ihc fatal dose in solution, the more the toxic effect is 

 reduced l)y the introduction of (piartz. Hence the range of concentrations, 

 iioth fatal and accelerating, is much greater in solution than in soil cultures. 



The report concludes with a bibliography of literature i-elating to the 

 sub.ject. 



Some investigations on the injury to plants by sewage, 1*. Ehrenrerg 

 iZtschr. I'lUnizriih-niuk.. 10 H'.xk;), \o. J,, pp. ]!)3~20.>).—\ study was made to 

 determine the effect on i)lant life of sewage from a sewage-disjiosal farm. 



It was found that the paper pulp, fat, and various salts carried by the sew- 

 age had an injurious effect on all crops experimented with, the i)ai)er pulp and 

 fat being mechaniciilly injurious, while th" salts were chemically noxious. In 

 the case of icrcals the i)lats receiving the sewage W(>re later in ripening and 

 yielded less grain in jtroitortion to straw than wher(> no sewage was ai)plied. 

 In a nnnilier of iiist:iiH-es there seemed to be a greater tendency In jilant dis- 

 e.-ises (in (he treated plats. 



The influence of concentration of nutrient solutions on the development of 



2.'i577— No. 7— 07 3 



