36 Physiologie. 



Priestley, J. H., The effect of Electricity upon Plants. 

 (Bristol Naturalists' Society's Proceedings. Series 4. Vol. I. Pt. 3. 

 p. 192—203. 1907.) 



The Chief object of this paper is to give an account of some 

 Experiments made by Mr. J. E. Newman with the view of employing 

 electricity as a Stimulus to plant-growth upon a large agricultural scale. 



A Short notice is lirst given of a number of scattered cases from 

 the eighteenth Century onwards in which a favourable effect of 

 electricity upon Vegetation has been reported. 



In Newman's experiment of 1904, 500 Square yards of kitchen 

 garden were electrilied by the overhead discharge System and the 

 crops compared with control plots: Cucumbers 17% increase: Straw- 

 berries 36— 807o increase, Tomatoes no effect. An outbreak of a 

 bacterial disease on Cucumbers seemed much slighter with the 

 electrified plants. 



In another experimental plot, Carrots showed 50% increase and 

 Beets 30*^/0, with an increase of l°/o in the sugar content. 



In 1906 twenty acres of wheat were electrified with discharge 

 wires at a considerable height and a very high tension current; in 

 this case an increase in the crops of 39 to 29% over the control 

 areas is recorded the electrified wheat fetched a higher price as it 

 gave a better baking flour. 



The writer of the paper then carried out laboratory experiments 

 upon the nature of the apparent electrical acceleration of plant 

 development but no satisfactory clue was arrived at. No confirmation 

 of Pollacci's view that an electric current enables a leaf to form 

 starch in the dark could be obtained. F. F. Blackman. 



Reed, H. S., The Value of certain Nutritive Elements to 

 the plant-cell. (Annais of Botany Vol. XXI, p. 501—542, 2 figs. 



1907.) 



The author has made a careful study of the importance of the 

 various metallic Clements for growth of algae, protonemata, prothallia 

 and root-tips, in culture Solutions. The paper opens with a historical 

 account of previous researches on the importance of K. P. Ca. Mg. 

 The experimental part discusses the methods for obtaining neutral 

 non-toxic distilled water, the best microchemical tests for proteids 

 and fats and the relative merits of different mixed nutrient Solu- 

 tions. Beijerinck's formula is preferred to Knop's for algae as it 

 does not tend to become alkaline: for flowering plants in water- 

 culture the formula given in Pfeffer's Physiology is preferred. 



Omission ot K. from the culture was very injurious even with 

 fungi; and it is essential for starch formation and mitotic cell-division. 

 The lack of P. is still more injurious and it is in some wa}?- essential 

 for carbohydrate transformation. Ca is needed for the activity and 

 growth of chloroplasts; mitotic division took place in its absence but 

 cell-walls were imperfectly formed. Mg. was needed for activity of 

 chloroplasts and oil was not formed in Vaiicheria in its absence. 



It has previously been observed that if Ca. is absent plants are 

 less normal in the presence of Mg. than in its absence. So in some 

 way Ca (and to a certain extent Na) may act as an antidote to Mg. 

 Some evidcnce to this relation was found in the present research. 



The author makes the general conclusion that essential elements 

 function either (1) directly, as component parts of cell constituents 



