918 Brenchley.— The Development of the Grain of Barley. 
scales, in the composite curve (Fig, 22). This shows that the critical point 
at which maturation or ripening of the grain really begins occurs at the 
tenth or eleventh period, about fifteen or eighteen days before harvesting. 
Up to this time the diastatic power of the grain has been steadily increasing. 
Henceforward it as steadily and rapidly decreases. The dry weight of the 
grain, the phosphoric acid, nitrogen, and dry weight of the whole plant all 
Planf 
1000 Grains 
IOOO Grams 
1000 Grains 
IOOO Grains 
Plant 
1000 Grains 
6 9 12 IS 13 21 24 27 30 33 36 33 42 45 43 Days 
Fig. 22. Composite Curve. Plots A, B, c averaged for corresponding periods. 
Dry weight - — — - — — — — i division = 5 grammes 
Maltose produced * — „ ,, 
Nitrogen 1 division = 01 gramme 
P 2^5 * * ' ” •’ 
Dextrose — o— 0—0— 0— o— o— o— o— o— o— 0— o— ,, ,, 
reach their maximum at approximately the same period. The fact that the 
P 2 O s and nitrogen in the grain continue to rise is an indication of the fact 
that migration of food material from the stem to the grain continues 
steadily throughout the ripening period. One thing is noticeable— that the 
amount of dextrose present in the grain apparently does not bear any 
relation to the diastatic capacity at any given time ; the dextrose curve 
continues to fall for some time after the diastatic power has passed its 
