98 PHYSIOLOGY [BoT. Absts., Vol. Vlli, 



TOXIC AGENTS 



669. Berczeller, L. Uber Adsorption und Adsorptionsverbindungen V. Die Adsorp- 

 tionsverbindungen des Kupferhydroxyds. [Adsorption and adsorption compounds V. The 

 adsorption compounds of copper hydroxide.] Biochem. Zeitschr. 93 : 230-236. 1919. 



670. GuERiTHAULT, B. Sur la presence du cuivre dans les plantes et particulierement 

 dans les matieres alimentaires d'origine vegetale. [On the presence of copper in plants and 

 especially in foods of vegetable origin.] Compt. Rend. Acad. Sci. Pa,ris 171: 196-198. 1920. 

 — ^A description of the methods used in the determination of the amount of copper in plant 

 tissues. Analyses of 44 types of plants are given in which the amount of copper in the 

 ash varied from 63.6 per cent in sweet almond to 8.7 per cent in radish. — C. H. Farr. 



671. Maquenne, L., et E. Demoussy. Sur la toxicite du fer et les proprietes antitoxiques 

 du cuivre vi3-l.-vis des sels ferreux. [On the toxicity of iron and the antitoxic properties of 

 copper in the presence of ferrous salts.] Compt. Rend. Acad. Sci. Paris 171: 218-222. 1920. 

 — Iron salts in culture solutions are often altered into salts which are precipitated and which 

 in themselves are not toxic, but give rise to a toxic acid. Peas grown in a culture medium 

 in which iron and CaS04 were present showed the maximum growth. Growth decreases as the 

 iron content is increased. A considerable growth occurs if KH2PO4 and CaS04 are both pres- 

 ent. Ferrous salts are found to be always injurious, whereas ferric salts stimulate growth 

 if used in small amounts. Iron alum and ferric oxide retard growth in all parts of the plant 

 except in the stem, which is slightly stimulated. — C. H. Farr. 



672. Tratjbe, J., UND H. Rosenstein. Uber die Wirkung von oberflachenaktiven Stoffen 

 auf Pfianzensamen. [The action on seeds of compounds affecting surface tension.] Biochem 

 Zeitschr. 95 : 85-100. 1919. — Seeds of cereals after preliminary water imbibition were subjected 

 to the various organic compounds known to modify surface tension. In the case of volatile 

 agents the seeds were exposed to the vapors; otherwise they were placed in the liquid. The 

 results were noted in terms of per cent of germination and amount of growth. — In general the 

 work of earlier investigators is confirmed, that is, a variation from stimulation to inhibition 

 is correlated with increase in time of exposure to the agent. Narcotics, such as chloroform, 

 ethyl ether, urethane, etc., showed a range of action conforming, over a series, to their effect 

 as animal narcotics. With respect to germination and growth processes the phenomena 

 of reversibility and irreversibility of narcosis as well as of stimulation were established. — 

 Similar data w^ere obtained for a series of disinfectants, such as cresol and naphthalene. The 

 higher fatty acids, caproic and caprylic, were strongly stimulative to germination when 

 applied in small doses. — W. W. Bonns. 



673. Wientjes, K. Acceleration de la germination sous I'influence des acides. [Influence 

 of acids upon germination.] Recueil Trav. Bot. Neerland. 17:33-68. 1920. — The influence 

 of HCl, H2SO4, oxalic acid, and tartaric acid upon the germination of seeds of Phacelia tana- 

 cetifolia, Solanum Lycopersicum, Alisma Plantago, Epilobiurn hirsulum, and Lythrum Sali- 

 caria was determined. — There was no influence on Phacelia, Alisma, Epilobiurn, and Lyth- 

 rum, but with Solanum some acceleration of germination was observed. — J. C. Th. Uphof. 



ELECTRICITY AND MECHANICAL AGENTS 



674. Anonymous. Difference of potential in biology. Sci. Amer. Monthly 2: 122. 1920. 

 — An account of a report presented to the Societe de Biologie, Paris, March 13, 1920. It 

 concerns experiments on the electric phenomena associated with certain physiological proc- 

 esses of plants and animals. — Chas. H. Otis. 



