430 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
fication of guanidine carbonate, but it helps the nitrification of dried blood, 
piperidine, nucleic acid, alloxan, and asparagine. Liming a soil which has been 
partially sterilized with carbon bisulphide greatly increases its power of nitri- 
fication. Vanillin is non-toxic toward nitrification of piperidine, moderately 
toxic towards nitrification of dried blood and pyridine, and inhibitory towards 
nitrification of quinoline. The toxicity of vanillin is counteracted largely by 
lime. Pyrogallol retards nitrification of all compounds, except quinoline and 
piperidine. Salicylic aldehyde completely inhibits nitrification of all compounds 
except piperidine. 
A short bibliography is appended. — A. B. 
Soils, Acid, The Development of Soluble Manganese in. By M. J. JFunchess 
[U.S.A. Agr. Exp. Sfn. Alabama, Bull. 201, June 1918, pp. 37-78 ; 12 plates). 
— Acid soils from this experimental station are injured by addition of dried blood 
as a fertilizer, and this infertility is attributed to the formation of soluble man- 
ganese in the soil solution. The manganese is believed to be due to the action 
of nitric acid formed during nitrification when dried blood is used as a source 
of nitrogen. When ammonium sulphate is the source of nitrogen, nitrification 
is apparently unnecessary in order to increase the amount of soluble manganese 
in acid soils. The reduced growth is due to the direct action of manganese, 
and this acts upon the roots and to a certain extent upon the foliage. Water 
extracts of such soils are highly toxic to seedling plants. If, however, the man- 
ganese is precipitated into an insoluble form, the water extracts support a vigorous 
plant-growth. Precipitation by calcium, sodium, and potassium hydroxides 
are very effective in this connexion. The products of sulphofication are also 
effective in dissolving manganese in acid soils. Manganese salts applied to 
basic soils would be rapidly changed, the^'manganeseTpassing out of solution. 
When applied to"^ acid (soils, the manganese salts persist as such, and heavy 
application would cause injury. 
A short bibliography is appended. — A. B. 
Soils, The Cause of the Disappearance of Cumarin, Vanillin, Pyridine, and 
Quinoline in. By William J. Robbins (U.S.A. Exp. Sin. Alabama, Bull. 
195, June 191 7, pp. 48-64 ; 2 plates). — The much-debated question as to the 
toxicity of substances to plants when grown in soils containing such, was inves- 
tigated in this present paper. Previous investigators have found that such 
toxic substances are decidedly harmful to plant growth if present in soils, while 
others hold that some such compounds, if present, soon disappear, and therefore 
have no toxic action upon plants. The chemicals used in this work were vanillin, 
cumarin, pyridine, and quinoline, and these were added separately to soils at 
a concentration of 1 000 parts a million of air-dry soil. The first effect was 
to increase enormously the number of bacteria ; the number of Actinomyces 
colonies in soils treated with cumarin, vanillin, and quinoline, however, decreases. 
Steam sterilization of the soil produces material toxic to the growth of wheat 
plants. Soil micro-organisms destroy the toxicity of the steamed soil. The 
effect on the growth of wheat, of vanillin, cumarin, pyridine, and quinoline in 
sterile soil, and in soils which have been sterilized, reinoculated, and incubated, 
were compared. It was found that the toxic effect persists in the sterile soil, 
but largely disappears in the reinoculated soils. Specific bacteria were isolated 
from the soils which utilize cumarin, vanillin, and pyridine as food sources. 
The bacterium feeding upon vanillin will in pure cultures destroy the toxicity 
of vanillin to wheat, and the bacterium feeding on cumarin under similar con- 
ditions will destroy the toxicity of cumarin to'"wheat. The conclusion drawn 
is that the chief cause of the disappearance of the toxicity of cumarin, vanillin, 
pyridine, and quinoline in inoculated soils is due to the fact that they serve as 
food to definite species of bacteria. 
A short bibliography is appended. — A. B. 
Sorosporella uvella, a Fungus Parasite of Noctuid Larvae, Further Studies on. 
By A. T. Speare {Jour. Agr. Res. xviii. pp. 399-439, Jan. 1920; 6 plates). — 
This entomogenous fungus is recorded and described for the first time in the 
States. ^ 
An historical summary is given of this group of fungi, followed by a life- 
history and methods of cultivation on favourable media. The disease is easily 
transmitted to healthy insects, and under laboratory conditions a mortality 
of 60 to 90 per cent, was obtained. 
Two full-page sketches and six microphotographs complete the paper. 
G. F. W. 
