NOTES AND ABSTRACTS. 
225 
material has hurt the land temporarily ; therefore the results obtained in these 
experiments lead to the belief that the carbon dioxide content of garden soils is 
sometimes detrimentaLto the root development of some plants growing in the 
garden." 
These investigations emphasize the equal importance of soil aeration with 
moisture and suitable temperature. — R. J. L. 
Rose Midge, The. By E. R. Sasser (U.S.A. Dep. Agr., Bull. 778, May 1919 ; 
2 figs.) — The Rose Midge (Dasyneura rhodophaga Cog.) often does considerable 
injury to roses grown under glass, but it can be controlled, if not completely 
eliminated, in a short time by the careful application of tobacco dust on the 
soil, and nightly fumigation with tobacco, in the form of stems, nicotine papers, 
or one of the volatile nicotine preparations. — V. G. J. 
Seed Treatment, Pre-soak Method of. By H. Braun (U.S. Jour. Agr. 
Res. xix. July .1920, No. 8, pp. 363-392 ; 14 plates). — The widespread 
use of formalin and copper sulphate as germicides in seed treatment has often 
been attended by decreased and retarded germination. Experiments have 
shown that this detrimental effect can be avoided for standard varieties of 
wheat by soaking the seeds in water for six hours before treatment with formalin 
or copper sulphate. Soaking for ten minutes and covering for six hours (pre- 
soak method) is better than leaving in water for six hours before treatment. 
The saturation of the seed coat appears to be the factor counteracting the in- 
jurious effect upon germination. This acts by diluting the disinfectant as it 
diffuses into the tissues, and the author believes it to act as a stimulus to germin- 
ation. The bacterial " black chaff " of wheat has been controlled by this 
method. — A. B. 
Seedlings, Wheat, Effect of Lime upon Sodium Chloride, Tolerance of. By 
J. A. LeClerc and J. F. Breazeale (U.S. Jour. Agr. Res. xviii. No. 7, Jan. 
1920, pp. 347-356 ; 10 plates). — The work here reported is a continuation of 
work in Bull. 149, " Bureau of Chemistry." In this the effect of lime upon soils 
which had become acid by continued use of potassium chloride or potassium 
sulphate was pointed out. The present work details the equally important 
role of lime upon salts occurring naturally in " alkali " soils. The higher 
tolerance to alkali salts shown by plants in soil and sand than by those grown 
in water cultures is not due entirely to the physical effect of presence of solid 
particles of differences in fineness, but is also due to certain soluble substances 
present in minute quantities. Very small amounts of calcium oxide and calcium 
sulphate can overcome the toxic effects of sodium chloride and sodium sulphate. 
Magnesium sulphate and barium chloride were slightly antagonistic to sodium 
chloride ; but potassium chloride, sodium nitrate and sodium phosphate, ferric 
chloride and alum have no effect on the toxicity of sodium chloride. — A. B. 
Seeds of Cereals, Treatment by Dry Heat of. By D. Atanasoff and A. G. 
Johnson (U.S. Jour. Agr. Res. xviii. No. 7, Jan. 1920, pp. 379-390 ; 2 plates). — 
In the investigation of control measures for certain seed-borne diseases of cereals 
which are not affected by the ordinary chemical and hot-water treatment, the 
authors found that dry heat was particularly adaptable. Various cereals — ■ 
rye, wheat, barley, oats — when of good quality and well dried, are able to with- 
stand protracted exposures to dry heat at comparatively high temperature. 
It is definitely shown that seed infections from bacterial blight of barley 
(Bacterium translucens), and that of oats (Pseudomonas avenae), may be eliminated 
by exposing the infected seeds to dry heat at temperatures which leave the 
seed viable. The results of the experiments show that a number of seed-borne 
fungoid diseases, e.g. Wheat scab (Gibber ella saubinetii, Fusarium spp.), Leaf 
Blotch of Barley (Helminthosporium sativum) , are particularly checked when the 
infected seeds are given the dry -heat treatment, and this without any injury 
to the germinating capacity of the seeds. A list of literature is appended. 
A. B. 
Slug, The Gray Garden, with Notes on Allied Forms. By A. L. Lovett and 
A. B. Black (U.S.A. Exp. Stn., Oregon, Bull. 170, June 1920 ; coloured plate, 
14 figs.). — The garden slugs are voracious and omnivorous feeders, reproduce 
often, and in large numbers adapt themselves to all conditions, and maintain 
themselves against all odds. They have comparatively few natural enemies 
and are surprisingly resistant to poisons. 
Calcium arsenate, 1 part by weight to 16 parts chopped lettuce, is readily 
eaten and is highly toxic to slugs. This, in conjunction with dry Bordeaux 
mixture dusted over the plants, has proved a satisfactory method of controlling 
the pest. The treatment may need to be repeated once or twice at seven to ten 
days' intervals until injury is reduced to a minimum. — V. G. J. 
