330 
broken down under the stress of foreign competition had it not 
been for the perfect technology of its agriculturists. Asan example, 
= sho he Ble may be quoted. This plant contained originally but 
mall amount of sugar, and could only be used as a source of 
sog when e price of the latter was very high. With the fall 
in is came cum irr need for increasing the ‘percentage of 
sugar in the bee This was effected by utilising the fact 
that ees chaos: is a. so that by selecting artificially 
the roots richest in sugar, getting seed from these, planting the 
seed, again selecting the richest roots, and so on, a race of plants 
x at length obtained in which a high percentage of sugar is 
mal.* Accordingly the próduoems of beet-root seed in Germany 
have erected great laboratories in which the percentage of sugar 
in the roots is carefully determined. By applying the principle 
of artificial selection with regard also to the form and size of leaf 
and the purity of the sap, it has been found possible to improve 
the roots from year to year, so that now beet-sugar can easily 
hold its own against cane-sugar, and is indeed cheaper than flour, 
costing as it does in Germany less than a penny a poun 
Similar success has attended the efforts to increase the crops of 
different kinds of grain. The improvement in malt-barley has 
been specially marked. 
s been found that plants which have been highly cultivated 
en 
part in Germany, during the last ten years, yee chemistry of 
plants. The most interesting of these trace re chemical history 
of nitrogen as it passes from the atmosphere to the soil, then into 
the substance of plants, and finally back into the atmosphere. 
The corresponding cycle for carbon has long been known. 
Most plants assimilate nitrogen only in the form of compounds. 
As, however, the total quantity of nitrogen compounds in the 
atmosphere is comparatively small, there must be some other 
source of nitrogen for plants. Now the classical researches of 
f 
elementary nitrogen and so to leave a soil in which they have been 
grown richer in nitrogen compounds. It has been found that the 
power of acting as nitrogen collectors isalways associated with the 
presence of micro-organisms on the roots, and that the assimi- 
lation of the nitrogen is in some ake not understood due to the 
micro-organisms. "The r recognition of the power of leguminous 
plants to act as nitrogen collectors is manifestly of great practical 
importance, for it shows clearly that the best rotation of crops 
is one in which a leguminous crop is followed by one of 
nitrogen consumers, /.^., plants which cannot assimilate nitrogen 
directly. 
Leguminous plants, whether first used as fodder for animals or 
simply left to decay in the soil, have their albumen changed 
in the first instance to amides, ‘which under the influence of 
oai comae clo ut 
* See Kew Bulletin, 1897, pp. 317, 318. 
