26 EXPEKIMENT STATION RECORD. 



In field experiments applications of sulphur were beneficial except when the 

 soils were abundantly supplied with other fertilizing constituents. Potatoes 

 were especially benefited by applications of sulphur. Cereals were injured by 

 such applications on light soils poor in calcium carbonate. An application of equal 

 I^arts of sulphur and nitrogen gave as good results as a complete mineral fer- 

 tilizer containing phosphates, potash, and lime. 



The author attributes the fertilizing effect of sulphur to its action on the 

 micro-organisms of the soil and the progressive transformation of sulphur 

 into sulphuric acid, thus supplying sulphur to the plant and rendering soluble 

 other mineral constituents of the soil, particularly potash. 



The fertilizing action of sulphur, A. Deholon {8ta. Agron. Aisne Bui., 1912, 

 pp. 33-41). — This is an account of experiments reported abova 



AGRICULTTJEAL BOTANY. 



The cause of growth in plants, I, G. A. Bobowikow (Biochem. Ztschr., ^8 

 (1913), No. 3, pp. 230-2^6, figs. 3). — ^As a result of several series of studies 

 carried out on the growth of plants as afl'ected by various acids, bases, and 

 salts, the author believes that growth is possible only under conditions favor- 

 able to the process of hydration of the colloids; that rapidity of growth is 

 favored by such conditions, and checked (even if death is not induced through 

 coagulation of the colloids) by their absence. The most important factors in 

 growth are thought to be, under ordinary conditions, warmth and the organic 

 acids. It is said that the degree of influence exerted by the acids depends not 

 only on the concentration of the hydrogen ion, but also upon the character 

 and tendency of the other ion as favorable or unfavorable to growth. Further 

 investigations are proposed regarding these points, also on the significance of 

 cell turgor to growth. 



The role of acids in germination, Germaine Promst (Bui. Soc. Nat. Agr. 

 France, 12 (1912), No. 10, pp. 916-922).— A study was made of the effect of 

 various organic and inorganic acids on the germination, respiration, growth, 

 etc.. of plants. Fleshy seeds and those having dry pericarps were used. 



In general the fleshy seeds seemed better able to profit by the presence of 

 acids than the others. The germination was accelerated by dilute solutions of 

 citric, malic, tartaric, oxalic, acetic, hydrochloric, and sulphuric acids. Dif- 

 ferent species of plants responded differently to the several acids and the 

 optimum concentrations ranged from 0.5 to 5 parts per 1,000. Growth followed 

 increased turgescence, and this was found to be materially influenced by the 

 acids. The organic acids proved superior in this respect. 



The author claims that the seeds of maize, wheat, and gourd contain a form 

 of pepsin that is active only in the presence of an acid, while seeds of lupine 

 and some other plants contain a trypsin that is favored by an alkaline medium. 

 The acid solution is held to act upon the diastases in seeds through absorption 

 and to favor or retard germination according to the nature of the ferment. 



Sunlight and plant assimilation, A. Muntz (Compt. Rend. Acad. Sd. 

 [Paris], 156 (1913), No. 5, pp. 368^370).— The author has made a study of the 

 effect of strong and diffused light on plant assimilation. The observations 

 carried on during 1910, 1911, and 1912 are cited, from which it appears that 

 alfalfa produced less material per square meter in 1911, a summer unusually 

 free from clouds, and a larger yield of green material in 1910, when rain was 

 frequent and cloudy skies prevailed. 



In comparison witt these field observations, experiments were carried on in 

 which equal amounts of water were given to alfalfa during the same period 



