AGEICULTUEAL BOTANY. 325 



had an important effect on the growth of rye. In 1910 he continued his experi- 

 ments, using barley as a representative of cereals, the ash of which is said to be 

 acid in reaction, and sugar beets, the ash of which is allialine. The plants were 

 growTi in water cultures containing a nutrient solution, to certain series of 

 which were added a number of comiwunds, as silica, aluminum hydrate, straw 

 gum, calcium laurate, palmitate, humate, carbonate, and zeolite, and sodium 

 zeolite. After about 4 months the plants were analyzed and their ash, dry 

 matter, etc., determined. 



As a result of this investigation the previous conclusion is confirmed that 

 certain hydrolyzable salts which do not act as plant nutrients still have a very 

 important role in connection with plant growth. Barley and probably all of the 

 Gramine^e do not develop normally except in solutions containing colloidal silicic 

 acid, and they were found to be extremely sensitive to certain organic com- 

 pounds, especially humic acid. On the contrary, the sugar beet flourishes in the 

 presence of humic acid in the nutrient solution, but suffers considerably in the 

 presence of silicic acid. 



In making some deductions from his experiments the author states that the 

 favorable action of ammonium sulphate as compared with nitrate of soda on the 

 Graminepe may be explained by the fact that the ammonia is physiologically 

 acid and its introduction into the soil probably results in a mobilization of the 

 silicic acid. He also states that manure applied to spring grains has a detri- 

 mental effect, due to the formation of calcium humate, which is injurious to 

 grasses. 



Combined influence of zinc and mang'anese on the development of Asper- 

 gillus nig-er, G. Bertrand and M. Javillieb (Compt. Rend. Acad. ScL [Paris], 

 152 {1911), Mo. 13, pp. 900-902). — In a previous publication attention is called 

 to the catalytic action of certain substances and their effect on plant growth 

 (E. S. R., 21, p. 723). In a subsequent paper a report is given on the effect 

 of manganese on the development of A. niger (E. S. R., 25, p. 127), and in the 

 present article an account is given of the combined action of zinc and man- 

 ganese used in considerable dilution upon the growth of this fungus. 



It was found that when added to cultures containing the fungus the com- 

 bined influence of zinc and manganese was of decided advantage, not only when 

 used in proportions which previous experiments had shown were the optima 

 for the different compounds used singly, but also when used in less quantity. 



The authors claim that the catalytic action which various substances have 

 toward plant cells is of especial economic importance. 



The retention of mineral matter by annual plants, and the distribution 

 of the dry matter, total ash, and nitrogen, G. Andre (Compt. Rend. Acad. 

 8ci. [Paris], 152 (1911), No. 12, pp. 777-7S0).— In a previous paper (E. S. R., 

 24, p. 721), the author reported the retention of practically all the mineral 

 matter taken up through the roots of annual plants. In the present article the 

 results are given of studies on the distribution of dry matter, ash, and nitrogen 

 in the roots, stems, leaves, and fruits of carnations at various stages of growth. 



The dry matter of all parts of the plants constantly increased up to maturity. 

 The total weight of ash increased in all the plant organs except in the leaves, 

 where there was a loss of about 5 per cent between the beginning of maturity 

 and its final completion. The total nitrogen increased in the roots until after 

 flowering, when it decreased slightly, gaining again at maturity. In the leaves 

 the total nitrogen attained its maximum at the period of flowering. In the 

 stems and fruits it increased with practically every succeeding stage of growth. 

 The percentage of nitrogen in comparison with the dry weight diminished con- 

 stantly through the different periods, although the loss was very slight in the 

 fruits. 



