BOOKS AND CURRENT LITERATURE 



The Effect of Light on Growth. — The results of the researches 

 of the reviewer pubHshed in 1903 made untenable the inference that 

 light acts as a retarding agent upon the growth of plants (The influence 

 of light and darkness upon growth and development Mem. N. Y. Bot. 

 Garden. 2: p. 307. 1903). This conclusion was reached after an 

 extended study of the behavior of a hundred seed-plants in darkness as 

 compared with their normal development. The ageworn inference, 

 however, was convenient to use pedagogically and its vogue has con- 

 tinued up to the present, being embodied in most of the text-books, 

 especially those in which no analysis is attempted of the complicated 

 play of forces which contribute to the dimensional alterations con- 

 stituting the external expression of growth. Now comes Dr. Blauuw 

 of Haarlem who in the consideration of the "Primary photo-growth 

 reaction and the cause of the positive phototropism in Phycomuces 

 nitens (Koninkl. Akad. van Wetensch. te Amsterdam. 16; Feb. 26, 1914) 

 finds that an eight-sided illumination of a sporangiophore of Phycomyces 

 causes an acceleration after 3 or 4 minutes to two or three times the 

 normal rate of elongation. The continuation of the illumination is 

 accompanied by a lessening acceleration for as much as 16 minutes 

 when the rate decreases and may even fall below the normal for a siiort 

 time to return again to the normal. " Incidentally the results of Blauuw 

 show that the phototropic curvatures are the direct result of an asym- 

 metrical modification of the growth of the different sides of the cylindri- 

 cal cells. The actual direct effect of the light is taken by the author 

 to include modifications of the stretching capacities of the cell walls, 

 reestablishing the old theory of De Candolle. — D. T. M. 



Transpiration as Affected by Surface Films. — This paper^ con- 

 tains some strikingly significant and interesting results upon the influ- 

 ence of Bordeaux mixture of two different concentrations and of char- 

 coal, lime, lime-sulphur, clay, etc., employed as dusts, upon the rate 

 of water loss from castor beans and tomatoes. Both potted plants 



' Duggar, B. M. and Cooley, J. S. The Effects of Surface Films and Dusts 

 on the rate of Transpiration. Ann. Mo. Bot. Gard. 1: 1-22, PI. 1. 1914. 



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