DISEASES OF PLANTS. 243 



impurities as ferrous sulphate, calcium carbonate, magnesium oxid, and mag- 

 nesium carbonate, but this retardation is not due to the diluent action of the 

 salts in question. The crystallization may also be delayed by various inorganic 

 salts and organic substances, saccharose being particularly effective. 



Bordeaux mixtures, after carbonization, are slightly soluble in pure water 

 and dissolve readily in water containing carbon dioxid in solution. They are 

 also soluble in water containing ammonia salts, and alkaline Bordeaux mixtures 

 are soluble in solutions containing dextrose, saccharose, and some other organic 

 substances. The physical state of the copper precipitate was found to be af- 

 fected, irrespective of the ratio of cupric sulphate to calcium oxid, by the dilu- 

 tion of the salts and the manner in which they are brought together and the tem- 

 perature of the water. After the copper and lime have been brought together a 

 slight delay in stirring the mixture was found not to affect materially the physi- 

 cal state of the precipitate, nor did long-continued stirring materially affect it. 

 Three types of Bordeaux mixture are recognized, neutral Bordeaux mixtures, 

 of which the Woburu Bordeaux mixture is a type, slightly alkaline Bordeaux 

 mixtures, and strongly alkaline or basic mixtures. 



Notes on the preparation of Bordeaux mixture, O. Butler {New Hampshire 

 8ta. Circ. 15 (191.',), pp. 10, figs. 2). — This circular gives some practical deduc- 

 tions from the studies described above, treating principally of the nature of 

 Bordeaux mixture, effect of method of mixing, relative value of hydrated lime 

 and quicklime, effect of temperature on keeping quality, methods for preventing 

 deterioration, tests for soluble copper, and descriptions of proprietary Bordeaux 

 mixtures. 



Of practical importance attention is called to the fact that hydrated lime is 

 not to be recommended in lieu of quicklime in the preparation of this mixture 

 except where quicklime is not obtainable or is of too poor quality to be advan- 

 tageously used. The studies on temperature showed that low temperatures, 48 

 to 50° F., for making the mixtures and keeping them are more satisfactory than 

 higher temperatures. In testing for excess of copper the author suggests testing 

 for alkalinity will be usually sufficient, but he states that the 4 : 4 : 50 mixture, 

 which is commonly used, has an excess of lime so that testing for copper would 

 be superfluous. 



The action of Bordeaux mixture on plants, B. T. P. Barker and C. T. 

 GiMiNGiiAM (Ann. Appl. Biol, 1 (1914), ^No. 1, pp. 9-21, figs. 6).— Recent tests 

 continuing previous work (E. S. R., 25, p. 458), made on injured and uninjured 

 apple seedlings one year old and sprayed with Bordeaux mixture, showed that 

 even slight fresh injuries to the leaf cuticle will permit of scorching by that 

 fungicide; also that weather and season as well as long contact with the mix- 

 ture are influential in determining susceptibility to such injurious influence. 



Cells with readily premeable walls may absorb dissolved copper and be killed 

 thereby. The nature of the cell wall is said to determine the interaction, when 

 such occurs, between cells of higher plants and the copper compounds, some 

 types of leaves absorbing and translocating copper without local injury. Cop- 

 per may also be carried up through the roots to the aerial parts of some plants 

 without apparent injury to the cells through which it passes. 



Spreading and adherent sprays, V. Vermorel and E. Dantony (Rev. Vit., 

 Ifl (191 If). No. 1063, pp. J,93. //.9./,).— The authors, replying to questions from 

 vine growers, give directions for the preparation and application of sprays for 

 which, when used as prescribed, superior effectiveness with economy is claimed. 



The compatibility of insecticides and fungicides, G. P. Gray (Mo. Bui. 

 Com. Hon. Cal., 3 (1914), No. 7, pp. 265-275) .—The relations of compatibility 

 or incompatibility of various mixtures and solutions in use against insects and 



