28 EXPERIMENT STATION RECORD. 



The influence of chemicals on the germinating capacity of dodders, 

 G. D'iPPOLiTO (Staz. 8per. Agr. Ital., U {1911), No. 3-4, PP. 301-308; ais. in 

 Riv. Patol. Vcg., 5 {1911), No. 6, p. 86; Chem. ZentU., 1911, II, No. 6, p. 370; 

 Jour. Chem. Soc. [London], 102 {1912), No. 591, II, p. 82). — Experiments are 

 reported on the use of c-liemicals for destroying Cuscuta arvensis and C. trifoUa. 



Ammonium nitrate, sodium carbonate, calcium cj^anamid, and formalin were 

 found to kill dodder seeds, while potassium nitrate and carbonate did not 

 entirely inhibit their germinating capacity. Sodium and calcium nitrates were 

 less efficient, and magnesium sulphate is said to have had hardly any action. 



The author recommends, for destroying dodder seeds in the soil, treatment 

 with either a 2 per cent solution of ammonium nitrate or a 1 per cent solution 

 of formalin. 



The sterilization of seed in relation to the micro-organisms contained by 

 them, G. Rossi {Rend. Soc. Chim. Hal., 2. ser., 2 {1910), pp. 276-280).— The 

 difficulty of completely sterilizing seed without destroying their germinative 

 ability is well known. The author gives the results of experiments to secure 

 the sterilization of a number of kinds of seed. Lots of 25 seeds of each kind 

 were placed for 3 hours in a 3 per cent solution of hydrogen peroxid. after 

 which single seeds were transferred to tubes and placed in an incubator, where 

 they were ke]it for 25 days. 



No species of seed remained completely sterile, molds and bacteria making 

 their appearance in different lots in from 5 to 15 days. Fifteen tubes contain- 

 ing seed of maize, 10 of dried peas, 2?> of fresh peas, and 8 of lentils became 

 infected. Only 1 each of chick-peas and Dolichos and 2 of wheat were con- 

 taminated at the end of the experiment. 



Influence of continued electric currents on the growth of plants, F. 

 KovEssi {Compt. Rend. Aead. Sci. [Paris], 154 {1912), No. 5, pp. 289-29 1>).— The 

 author reports experiments with wheat, supplemented by observations on rye, 

 oats, barley, velch, beans, various grasses, and a number of species of trees, as 

 well as mosses, algsp, and various fungi. 



The results obtained confirnitxl the conclusions of previous investigators that 

 a continued electric current exerts a retarding effect on growth and is decidedly 

 injurious to the germination of seed and the development of plants. The factors 

 which determine the effect of electricity on plants are summarized, and it is 

 shown that the intensity and potential of the current, the conductivity of the 

 medi\un, and the various physical and biological factors which influence the 

 life of the plant, as well as the chemical changes which take place, all exert an 

 important role in plant growth as influenced by electricity. 



The liberation of heat in respiration, G. J. Peirce {Bot. Gaz., 53 {1912), 

 No. 2, pp. 89-1 ]2, dgms. 8). — In a previous note (E. S. R., 20, p. 734), the author 

 gives a description of the value of Dewar flasks as respiration calorimeters for 

 class use. Subsequent studies have confirmed their usefulness in physiological 

 experiments. In the present paper an account is given of their use in germina- 

 tion studies with peas, and also of a study on the heat liberated by a mouse 

 placed in a flask. 



In the series of experiments with peas, seeds of different ages were ger- 

 minated in the flasks. It was found that the amount of heat liberated by germi- 

 nating peas decroasetl with their age, and apparently that the amount of heat 

 liberated during germination may be used as an index of the age or freshness 

 of seed. 



Discussing the significance of heat liberation in respiration, the author calls 

 attention to the fact that there is a much greater release of energy in the form 

 of heat than can possibly be used by the organism, and states that it is evident 



