14 



After completion of fermentation 5 c.c. alumina cream is added, 

 the solution made to 100 c.c. at 15°, filtered, and 50 c.c. used for re- 

 duction. The difference between the average reduction with a, b, 

 c and the average of d and e gives the reduction due to maltose. 



(4) Pentoses. These are approximately determined in 50 

 c.c. of A, by distilling with hydrochloric acid according to the 

 A.O.A.C. method weighing as phloroglucide. 



(5) When the reduction due to pentose and maltose has been 

 allowed for in 1, the remaining direct reduction is due to dextrose 

 and laevulose ; the actual proportions of these two sugars are cal- 

 culated from the reducing power combined with the corrected rotation 

 as suggested by Brown and Morris in the 1 893 paper. 



III. "A Simple Laboratory Apparatus for the Continuous 



Evaporation of Large Volumes of Liquid in Vacuo." 

 W. A. Davis. Journal of Agricultural Science, 1913. 

 5, 434—436. 



A description of a simple apparatus used in the above analytical 

 process. 



IV. "The Soil Solution and the Mineral Constituents of the 



Soil:' A. D. Hall, Winifred E. Brenchley and 

 Lilian M. Underwood. Philosophical Transactions 

 of the Royal Society, 1913. 204, 179—200. 



Solutions were made by extracting the soils from certain of the 

 Rothamsted plots on which wheat and barley had been grown for 

 60 years and upwards. Wheat and barley were grown in these 

 solutions, which were renewed fortnightly. The comparative growth 

 in the solutions was closely parallel to the growth of the crop on the 

 plots in the field and corresponded to the composition of the solutions. 

 The composition of the solutions as regards phosphoric acid and 

 potash corresponded to the past manurial treatment of the soils and 

 to the amount of phosphoric acid and potash they now show on 

 analysis. Growth in the soil solutions agreed with the growth in 

 artificial culture solutions containing equivalent amounts of phos- 

 phoric acid and potash. Growth in the soil solutions from imperfectly 

 manured plots was brought up to the level of that in the solutions 

 from completely manured plots on making up their deficiencies in 

 phosphoric acid and potash by the addition of suitable salts. The 

 phosphoric acid and potash content of the soil solutions w r as of the 

 same order as the phosphoric acid and potash content of the natural 

 drainage water from the same plots. 



Wheat grew as well as barley in the solutions of the wheat soils 

 and vice versa. In similar sets of solutions from the same soils 

 the growth of buckwheat, white lupins and sunflowers corresponded 

 with that of wheat and barley. Boiling effected no alteration in the 

 nutritive value of the soil solutions. 



In nutritive solutions of various degrees of dilution the growth of 

 plants varied directly, but not proportionally, with the concentration 

 of the solution, though the total plant food present in the solution 

 was in excess of the requirements of the plant. When the nutrient 

 solution was diffused as a film over sand or soil particles, as in 

 nature, there was no retardation of growth due to the slowness of 



