January I, 1914] 
NATURE 
515 
‘“‘single-plot method”’ serves the purpose very well. 
Another fact which had to be demonstrated and where 
the same method suffices is that in the case of most 
of the late-cropping varieties of potatoes the use of 
seed from certain districts in Scotland or the north of 
Ireland is profitable. But there are many cases where 
the somewhat crude single-plot method gives only 
indefinite results, and careful investigation has shown 
it to be incapable of revealing differences less than 
Io Or 15 per cent.; more refined methods are needed 
as soon as quantities of this order are to be dealt 
with. Prof. Wood went on to deal with some of 
these new methods and to urge their more general 
adoption in field work. 
The address was followed by a paper by Prof. 
Fraser Story, Bangor, on methods of German forestry. 
The five principal trees occurring in the German 
forests are Scotch pine (45 per cent.), spruce (20 per 
cent.), beech (14 per cent.), oak (7 per cent.), and 
silver fir (3 per cent.) The commonest method of 
regenerating the pine forest is by planting one- or 
two-year-old seedlings, the scanty foliage of which 
resists drying in sandy soils better than larger plants. 
In the case of spruce, on the other hand, transplant- 
ing material is used because the tree is grown in 
hilly or mountainous districts where there is more 
precipitation and greater danger of suppression by 
weeds. Beech and silver fir req ic shade when 
young, and therefore natural regeneration is resorted 
to, so that they may receive the shelter they need from 
the parent trees. Oak is generally raised from the 
acorn sown by hand, usually in a sheltered wood. 
Mr. Collinge followed with a description of a pecu- 
liar disease of cereals and roots and the action of 
sulphur and lime. The disease is known as ‘ May- 
sick,” and it is most evident on wheat. Mr. Collinge 
considered it is due to bacteria which interfere with 
the nutrition of the plant. Sulphur and unslaked 
lime are found to be successful remedies. 
The growing of linseed as a farm crop was next 
discussed by Mr. Duncan Davidson. Experiments 
made in this country during the last three years show 
that the crop can be successfully grown, that 10 to 
15 cwt. of linseed per acre can be obtained on medium 
land at a cost of about 6/., while the present price of 
the same quantity of linseed meal is 101. The climate 
both of England and Wales is found to be quite suit- 
able for the crop, and any soil of good texture and 
depth and not likely to dry out is suitable. The best 
time for sowing seems to be from the middle of April 
to the middle of May, but the seed at present obtain- 
able is quite unsuitable owing to its mixed origin, 
impure condition, and low vitality. There is also 
some difficulty about the thrashing; there is no market 
as yet for the straw. 
Prof. Barker and Mr. Gimingham gave a further 
account of their work on the fungicidal action of 
Bordeaux mixture which they attribute to the solvent 
action exerted by the fungus cells on the insoluble 
compounds of the spray fluid. They found that ger- 
minated spores and the thin-walled cells of the fungus 
hyphz exert a definite solvent action and are killed 
by the absorption of the dissolved copper. Similar 
results are obtained with root hairs and the roots 
of germinating seedlings. The cuticle of the upper 
epidermis of apple leaves, however, seems to be prac- 
‘tically impermeable during spring and summer; at 
any rate, no injury follows spraying so long as the 
cuticle is unbroken. In autumn, however, the cuticle 
is more permeable and death results more easily. 
The second day was devoted to a joint discussion 
with the Botanical Section on the problems of barley 
production. Mr. E. S. Beaven opened with a very 
good account of the experiments he has been carry- 
of barley for productivity. In the case of cereal crops 
the produce of dry grain on unit area is the sum of 
the following factors :—(a) number of plants surviving 
on the area at harvest; (b) the average dry weight 
per plant, which is the sum of the average number 
of stems per plant and the average weight per stem; 
(c) the ratio of the dry matter of the seed to the dry 
matter of the plant. These factors have been very 
fully investigated by Mr. Beaven, and a considerable 
interest attaches to the third, which he calls the 
migration factor, and which relates to the rate of 
transfer of material from the stem, leaf, and root 
to the seed. Mr. Beaven finds that this factor is 
high in the good yielding varieties, and in good. 
seasons, and he has got evidence that it is a definite 
character. It will be extremely interesting to follow 
up this migration factor and see in what way it is 
related to the other properties of the plant. 
This paper was followed by three others dealing 
with Irish barley experiments. These were com- 
menced in 1899 with the intention of improving the 
Irish barley crop. It was soon found that the 
varieties in common use were inferior to the best 
known elsewhere, and experiments were begun with 
other varieties, two of which turned out to be very 
useful, ‘“‘Archer’’ and ‘‘Goldthorpe.”” ‘‘Archer” is a 
narrow-eared barley, not usually grown on heavy soils 
or in late districts, but on light soils and in early 
districts, the result of its natural tendency to ripen 
late. ‘‘Goldthorpe,” on the other hand, is a typical 
wide-eared barley ripening about a week earlier than 
“Archer,” and therefore more suitable on heavy land. 
Mr. Bennett showed that the strain of ‘‘ Archer” 
raised in Ireland is just as good as that imported 
from elsewhere. By careful selection improvements 
have been effected, not only in cropping capacity, but 
also in quality. 
Mr. Hunter described the continuation of these 
experiments and the method of selection now in use 
at Ballinacurra. For the past two years a large 
number of plots on a very small scale are set up, and 
consequently a number of pure lines can be inves- 
tigated. 
Dr. Hackett discussed the results from a statistical 
point of view. 
Another joint discussion dealing with live-stock 
problems is reported in the account of the Physio- 
logical Section, and need not be further dealt with 
here (see Nature, December 18, 1913, p. 462). 
‘The Utilisation of Sewage in Agriculture’’ formed 
the subject of a paper by Dr. Grossmann. He attri- 
buted the unsatisfactory results obtained in farming. 
with sewage sludge to the fatty matter invariably 
present, and described a process whereby the dry 
sludge is mixed with a small percentage of acid, and 
subjected to the action of superheated steam, which 
carries off the fatty matters, whereby an inodorous 
brown powder is obtained, containing on an average 
I-53 per cent. of nitrogen, 3 per’ cent. of calcium 
phosphate, o-5 per cent. of potash, and 30-40 per cent. 
of organic matter. It was stated that good results 
had been obtained by the use of this material as 
manure. The author considers that the process re- 
moves one of the great difficulties in dealing with 
sludge; hence the sewage engineer may now aim at 
producing more sludge than before. 
A group of three papers on soil followed. Dr. 
Hutchinson described experiments made in conjunction 
with Mr. McLennan showing that a partial sterilisa- 
tion effect, intermediate in character between that 
exercised by heat and mild antiseptics, could be 
brought about by treating soil with quicklime. In 
the cases presented somewhere about 1 per cent. of 
lime was necessary; after a certain incubation period 
ing out for some years at Warminster on the selection | the soil bacteria then began to multiply rapidly and 
NO. 2305, VOL. 92] 
