238 JOURNAL ^OF THE ROYAL HORTICULTURAL SOCIETY. 
out the northern forests of spruce and fir, and is said to be one of the most 
destructive of Polypori. There, it is recorded as attacking the white and red 
spruces, Balsam firs, Thujas, and Weymouth pine. In Britain P. Schweinitzii 
has hitherto been regarded as a rare species. It seems to be becoming much 
more common, however, and may yet have to be regarded as a great danger to 
coniferous forests. It attacks Douglas fir and Sitka spruce in Perthshire, and 
Scots pine in Midlothian, as well as larch in England. 
Evidently the fungus first attacks the roots and then gradually works upwards 
into the trunk. There it spreads, causing decay in the stem up to a height of 
40 to 50 feet. 
The rate at which the fungus progresses seems to be variable. About six 
years ago a large Sitka spruce first produces sporophores at a few feet from the 
base of the trunk. To outward appearance the tree remained healthy till it 
was broken over by wind two years ago. The outer wood, to about 6 to 8 inches 
in width, was then found to be the only sound part in a butt 3 feet in diameter 
at breast-height. About 18 feet of the stem showed more or less distinct rings 
of rot. 
The following remedial and preventive measures might be suggested : 
(1) Cut off affected roots well above the place where the last sign of rot 
appears, and tar the wound. 
(2) Collect and burn sporophores while young. 
(3) Cut out badly attacked trees and plant hard woods in their places. 
A , D , Wm 
Potassium Cyanide and Ether, Similarity in the Effects of. By W, J. V« 
Osterhout (Bot. Gaz. vol. lxiii, No. 1, Jan. 1917, pp. 77-80; with 1 fig.). — In 
common with such typical anaesthetics as ether and chloroform, potassium 
cyanide produces a temporary decrease in permeability. The author suggests 
that this does not show that anaesthesia is a form of asphyxiation, but that 
it is more probable that the effect produced by KCN is the result of its inhibiting 
effect on oxidation. — R. J. L. 
Potato Scab and Sulphur Disinfection. By C. D, Sherbakoff (U.S.A. Dep. 
Agr., Cornell, Bull. 350, Aug. 1914, pp. 709-743 ; 2 figs.). — Potato scab is 
widely distributed, and is characterized by roughened spots which may form 
deep pits in the outer skin of the tubers. The disease is due to the fungus 
Actinomyces scabies (Thaxter) Giissow. 
From the experiments, the author finds that if 450 to 900 lb. of flowers of 
sulphur to the acre are broadcast on land, scab is considerably reduced. 
If, however, lime and sulphur are added together in equal proportions the 
fungicidal power is reduced to nil, but if 400 lb. of lime are mixed with 900 lb. 
of sulphur to the acre and placed on land, the fungicidal power is not diminished 
and the crop is considerably improved. It is noticed that sulphur added to the 
fertilizer reduces its value. — A. B. 
Potato Seed for Northern Nebraska. By R. A. Emerson (U.S.A. Exp. Sta. 
Nebraska, Bull. 146, Dec. 191 4). — It is suggested that the ideal potato for any 
district or set of conditions is probably best produced in that district or 
under those conditions. In East and South Nebraska, however, it has been 
found that the stock deteriorates so rapidly that fresh seed has to be imported 
every two or three years, and any long series of breeding operations has 
been impossible. The Nebraska Experiment Station, however, does not con- 
sider this state of things inevitable. Two methods of managing a crop — 
by frequent surface tillage in the usual way and by treating with a mulch — were 
tried, and an elaborate series of tests and cross-tests clearly brought out that 
the mulching system was most suited to that region. It is hoped in time to 
produce a strain of potato hardy enough for the severe Nebraska conditions 
by this method. 
The mulch should be about four inches deep after settling, and may consist 
of hay, straw, stable litter, or other coarse material free from grain and noxious 
weed seeds. 
It must be remembered that these experiments were designed, not to test 
the effect on the growing crop, but to discover the best method of producing 
a good strain of seed. 
Each experiment, therefore, took two years to complete. — M. L. H. 
Potato, Spongospora subterranea and Phoma tuberosa on the Irish. By 
L* E. Melhus, J. Rosenbaum, and E. S. Schultz (U.S.A. Jour. Agr. Res. vol, vii. 
