Fbbetjakt 28, 1008] 



SCIENCE 



329 



shaking the filtrate with ether. The 

 ethereal solution contains the compound, 

 and this is obtained in a crystalline form 

 by evaporating the ether over water. 

 When pure, the compound is white, melts 

 at 98-99° and has the composition and 

 other properties of dioxystearic acid pre- 

 pared by oxidation of elaidic acid. 



Toxic Substances Arising During Plant 



Metabolism: Oswald Scheeinee and M. 



X. Sullivan. 



For the purpose of studying the factors 

 underlying the decrease in yield of plants 

 grown successively on the same soil, wheat 

 and cowpea were grown on different soils 

 until the yield of the plants became poor. 

 Water extracts of these soils proved to be 

 poor media for the respective plants. On 

 shaking the extract with carbon black and 

 filtering, they became far better media for 

 plant growth. It must be concluded then 

 that the soil extracts contained something 

 actually deleterious to the plant since the 

 carbon black made from natural gas acts 

 merely as an absorbing agent. 



From wheat-sick soil there was obtained 

 by steam distillation a crystalline body 

 which is toxic to wheat. From cowpea- 

 sick soil in the same manner a crystalline 

 body was obtained which is toxic to cowpea 

 but not to wheat. 



The Chemical and the Physiological Prop- 

 erties of a Solution of Hydrochloric 

 Acid and Sodium Chloride: Amos W. 

 Petees. 



The influence of neutral salts, e. g., 

 NaCl, extends to both chemical properties 

 of solutions and to correlated physiological 

 functions. The killing concentration of 

 HCl for protozoa is lowered by the addi- 

 tion of a concentration of NaCl which is 

 practically harmless when used alone. 

 This effect can be explained by the in- 

 creased acidity of the mixed solution, ac- 

 cording to Arndt, Euler and others. 



Colorimetric comparisons with methyl 

 orange, and inversion tests by the polari- 

 metric method, made with the dilute 

 solutions of these experiments, favored this 

 hypothesis, whether the solutions were 

 made with redistilled water or with the 

 original culture liquids. The increased 

 velocity of inversion due to NaCl disap- 

 peared when the acid products of the re- 

 action demonstrated by Kullgren in- 

 creased. 



The Endo and EJdo-invertase of the Date: 



A. E. Vinson. 



The invertase of the date remains in- 

 soluble in all ordinary solvents throughout 

 its green stages, but becomes readily soluble 

 on ripening. The change in the behavior 

 of the invertase toward solvents coincides 

 very closely in point of time with the 

 passage of the tannin into the insoluble 

 form. Tannin in relatively large amounts 

 does not retard the action of date invertase 

 either in the extract or in the pulp. 

 Soluble tannin, however, hinders the solu- 

 tion of date invertase in water, but the 

 invertase can be extracted by glycerine, 

 provided the glycerine is added at the same 

 time the tannin is added. Green date in- 

 vertase can not be extracted by crushing 

 and macerating the green fruit with 

 glycerine, therefore the invertase is not 

 rendered insoluble, under the conditions of 

 the experiment, by the escape of soluble 

 tannin on crushing the tannin cells. This 

 conclusion is confirmed by the behavior of 

 the invertase in the tannin-free portion of 

 the date after the tannin-bearing tissues 

 have been completely removed. There is 

 no direct connection between the change in 

 the state of the tannin and that of the 

 invertase. 



The inversion of cane sugar by the green 

 date pulp is not accomplished by the living 

 protoplasm liberating a soluble ferment 

 from a preexisting insoluble zymogen or 



