A GRAIN OF BARLEY. 107 
acid which always makes its appearance during the growth of the 
embryo. 
The experimental evidence on these points is, however, at the 
present time too meagre for us to decide between these two 
views. 
I will now show you on the screen the appearance which 
the starch granules present when being acted upon in a 
natural way during germination. Exactly similar corrosion 
and solution can be produced in the laboratory by the action 
of prepared diastase upon starch granules. 
Although the sugar which is first produced in all these 
re-actions is, as I have said, madfose, it is a very remarkable 
fact that the sugar which is found in partially germinated 
grain, and which has, so to speak, been intercepted between 
the reserve-starch and the growing tissue of the young plant, 
is chiefly cane-sugar, and we have yet to learn how and where 
this apparent transformation of maltose into cane-sugar takes 
place. This is not an isolated fact in vegetable physiology. 
We find exactly the same thing in other parts of plants 
where starch, which has been laid up temporarily in 
reserve, is again dissolved and rendered diffusible. There 
seems to be in the vegetable economy some very direct way 
of transforming maltose into cane-sugar, which, when 
thoroughly understood, will probably result in the artificial 
production of cane-sugar from starch, and a complete revolu- 
tion in the sugar-industry throughout the world. 
I have said hitherto but little about the nitrogenous matters 
which are necessary for the growth and development of plants. 
Whilst in green plants the necessary carbon is derived from 
the air, the equally necessary ash-constituents and nitrogenous 
substances owe their origin to the so#/, and enter the plant 
through its roots, in solution, in the large quantity of water which 
it is also the function of the roots to absorb. 
The nitrogenous food of plants consists of nitrates and 
ammonia-salts, which all good vegetable soils contain in small 
quantities. How these nitrogen-containing bodies come to 
