718 EXPERIMENT STATION RECORD. 



to pai-tial drying in the sun they will gradually turn brown. The reason for these 

 changes is sought, and it is believed that the development of the black color is due 

 to the action of oxidizing enzyms upon the tannin of the tea leaves. The author has 

 investigated the presence of various enzyms in the leaves and has come to the con- 

 clusion that the action of oxidase upon the tannin is quite evident, and the so-called 

 fermentation of black tea is due to the action of oxidizing enzyms in the tea leaves. 

 Oxidase, peroxidase, and catalase were tested for in green and black commercial tea, 

 but none were found present. This is explained to be on account of the heating 

 which takes place as a primary stage in the production of green tea, or as one of the 

 final stages in black tea manufacture. Investigations as to the action of iron and 

 manganese upon oxidizing enzyms were conducted, from which the author con- 

 cludes that proteids containing iron and manganese are present in tea leaves. 



On the econom.ic importance of Nitragin, Maria Dawson {Anii. BoL, 15 

 {1901), No. 59, pp. 511-519).— An account is given of experiments conducted with 

 peas in which the efficiency of Nitragin was tested. Two series of experiments were 

 conducted, in one of which the plants were grown in media previously sterilized for 

 24 hours at approximately 200° C, while in the second series the plants were grown 

 in the open air on unsterilized media. In the experiments with sterilized media the 

 plants were grown in large pots containing ordinary garden soil, a gravelly subsoil, 

 and pure silver-sand, with and without potassium nitrate. Before sowing the seed 

 they were sterilized by being immersed in a 1 per cent solution of mercuric chlorid 

 for 15 minutes. The Nitragin was applied directly to the pots. These experiments 

 were carried on foi 3 consecutive years with practically the same results. The 

 results obtained show that on ordinary garden soil, on sand, and on sand which had 

 received the nitrate, inoculation with Nitragin was accompanied by a loss in the 

 weight of the crop, while a small increase was secured in those plants grown on 

 gravelly subsoil. The plants grown in the sand showed a considerable increase in 

 the crop produced by a supply of nitrate alone, but inoculation with Nitragin in the 

 presence of a sufficient supply of nitrogenous food, whether in the form of humus 

 or of potassium nitrate, was not beneficial. In the open-air experiments the same 

 general conclusion was reached. The tubercle organisms were present in all types 

 of soil, though they seemed less abundant in clay and ]teat, and in these particular 

 soils alone a large number of infections resulteil from the inoculation. As regards 

 the relative weights of the crop an increase was observed only in the plants grown 

 in the gravelly subsoil, and even there it was very small. On peat, clay, loam, or 

 ordinary garden -soil the inoculation with Nitragin proved to be both useless and 

 superfluous. 



The nature of the bacteroids of the leguminous nodule and the culture of 

 Rhizobium leguminosarum, R.G.Smith {Proc. Linn. Soc. New South Wales, 26 

 {1901), pt. 1, PI). 152-15,5). — The author briefly discusses the views of Hiltner and 

 Stutzer regarding the nature of the bacteroids of the nodules observed on the roots 

 of leguminous plants. These authors appear to show that bacteroids are degenerate 

 or involution forms of Rhizobium leguminosarum. This opinion is not concurred in by 

 the author of the present paper. He claims that the branching forms are in reality 

 simple cells contained in a branching capsule, and that this is readily observed with 

 organisms grown in artificial cultures, as well as those taken from root tubercles. 

 Hiltner's claims that Bdcillm radidcola requires infusion of leguminous plants for 

 growth and development is not correct, as the author has successfully grown them 

 in extracts of various plants, grass doing as well as extracts of lupines or other legu- 

 minous plants, and fairly luxuriant cultures have been obtained upon a gelatin 

 medium containing glucose and inorganic salts. 



A description of certain bacteria obtained from nodules of various legu- 

 minous plants, S. BuRRAGE {Proc. Indiana Acad. Sci., 1900, pp. 157-161). — Studies 

 have been inaugurated to ascertain whether the same species of bacteria always occurs 



