error attaching to field plots of particular sizes. This work has 

 been supervised by Mr. W. B. Mercer, B.Sc, Vans Dunlop Scholar 

 of the University of Edinburgh. 



The following papers have been published during the year : — 



W. E. Brenchley. " The influence of Copper Sulphate and 

 Manganese Sulphate upon the Growth of Barley.'' 

 Annals of Botany. 1910. 24, 571. 



It has been maintained that all substances toxic to plants act 

 as stimuli at some stage of high dilution, but the author submitted 

 this statement to a very careful test in the case of barley seedlings 

 growing in water cultures without finding any evidence of stimulus, 

 even down to dilutions of one of copper sulphate in ten miUion 

 parts of water. A toxic effect is always manifest, though it is 

 greatly masked when the copper solution is added to a solution of 

 nutrient salts, and is not used in pure water. In this latter case 

 seedlings are very susceptible, being perceptibly checked and even 

 stopped in growth by the use of water which has been distilled from 

 the ordinary copper vessels of the Laboratory. The apparent 

 stimulus at higher dilutions may have been due to accidental vari- 

 ations, since the individuality of plants grown in water cultures is 

 very marked, and large numbers must be taken in order to obtain 

 smooth results. Manganese sulphate can hardly be regarded as 

 toxic for barley, though in moderate concentrations (more than 1 per 

 10,000) there is retardation of growth. At lower concentrations 

 (l per 100,000 and downwards) there is distinct evidence of stimulus. 

 Incidentally it was noted that at such concentrations as 1 in 10,000 

 manganese was taken up by the plant and excreted as peroxide on the 

 surface of the leaves. As manganese is universally found in plant 

 ashes, and has been considered by Bertrand and his co-workers to 

 aid in the actions on the oxidases of the leaf, it obviously stands in 

 a different position to toxic-substances like copper which have no 

 normal physiological function. 



E. J. Russell. " The Ammonia in Soils.'' Journal of Agri- 

 cultural Science. 1910. 3, 233. 



Considerable uncertainty attaches to the determination of am- 

 monia in soils, because in the methods usually adopted the alkali 

 attacks some of the organic compounds of nitrogen, and there is a con- 

 tinuous evolution of ammonia as long as the distillation is continued. 

 Distillation with alcoholic potash at reduced pressures shows a sharp 

 end point when the evolution of ammonia ceases, and with soils not 

 too rich in organic matter the same end point is reached by a single 

 distillation with magnesia and water at the same temperature. It 



