regulating Metabolism . 5 1 1 
‘The experiments made at the Woburn Fruit Farm by the Duke of 
Bedford and Mr. Pickering have brought into prominence the highly dele- 
terious effect of grass on the growth of trees and the earlier annual maturity 
of trees the roots of which are covered with grass. 
‘ Mr. Pickering, after testing various possibilities, has been led to assume 
that toxic substances are formed by the growth of the grass and that these 
affect the underlying roots of trees. Here, again, taking into account the 
pronounced aminophilic habits of the Graminiae, we are inclined to think 
that the roots of trees under grass suffer because they are more or less com- 
pletely deprived of the stimulus afforded by the greater proportion of 
ammonia and carbon dioxide in bare soils. 
‘ It has long been known that under certain conditions sulphate of 
ammonia has advantages over nitrate of soda as a nitrogenous manure. It 
is customary to attribute the difference to the fact that ammonia salts are 
less easily washed out of the soil. We are inclined to think that the stimu- 
lative influence of ammonia should also be taken into account. It is possible 
that the value of ammonia in comparison with other forms of nitrogenous 
fertilizer has been somewhat overlooked and attention concentrated too 
much on nitrification in soils. 
‘ Lastly, we may refer to the nodular growths on the roots of legumi- 
nous plants ; these are known to be most essential to the proper growth of 
the plant but their function is by no means clear; it is well known that 
they are the seat of bacteroids and it may be that these function as assimi- 
lators of atmospheric nitrogen gas and convert it into ammonia ; or it may 
be that they exercise digestive functions and serve to “ deamidate ” amino- 
compounds. At all events, they are distinctly alkaline, whereas the root 
sap is acid. Moreover, it has been shown by Hutchinson and Miller that, 
when distilled with magnesia under reduced pressure, the nodules furnish 
more ammonia than do the roots (0-043 P er cen t- against 0-016 per cent.). 
We suggest that some part at least of the influence exercised by the 
nodules may be due to their aminogenetic power. We propose to make 
this assumption the basis of experimental inquiry.’ 
Most leaves become more or less brown when exposed to the action of 
either chloroform or toluene ; the most striking exemplification of this 
change that we have met with is afforded by Aucuba Japonica, the common 
spotted Japanese laurel ; when subjected to the action of substances which 
grains, at all events, would be to steep them in sulphuric acid and then to wash thoroughly with 
sterilized water under antiseptic conditions. 
At a recent meeting of the Institute of Brewing (Journ. Inst. Brewing, No. 3, vol. xvi, 1910, 
pp. 253, 259), when German brewing practice was under discussion, surprise was excited by the 
statement that it had been found advantageous to steep barley for malting in weak sulphuric acid ; 
it was suggested that sulphurous acid was meant but this was denied and reference was made to 
Adrian Brown’s observations as showing that the acid would not enter the grain ; but the obvious 
value of such treatment was in no way emphasized. 
