388 BOTANICAL GAZETTE [way 
hastened the germination of barley. He believes the temperature 
at which small grain will germinate is a measure of the degree of 
after-ripening. Thus, if seed will not grow at 13-15° C., preliminary 
drying is necessary; while if the seeds are capable of growing at 
30° the process of after-ripening is complete. He believes the 
after-ripening is but the completion of the ripening processes in 
seeds which have been harvested so late that normal ripening has 
not occurred. ZADE (67) notes the delay of germination of freshly 
harvested A. fatwa, and that it may be influenced by various exter- 
nal factors, but does not attempt to explain the effects of these 
various factors. He finds the delay is much shorter in seed kept 
in dry air of the laboratory than in that lying in the field, due as 
he believes to the difference in temperature. JANSON (38) notes 
two degrees of maturity in barley and oats, which he calls “yellow- 
ripeness” and “‘dead-ripeness.”’ The ripening of oats up to the 
yellow stage results in a larger increase in the protein stuffs. After 
yellow-ripeness one-third of the total increment occurs, and is only 
nitrogen-free stuffs. He thus believes too early cutting results 
in considerable carbohydrate loss to oats, for the effect of after- 
ripening extends only to the early stages of normal ripening, which 
concerns proteins chiefly. Krrsstinc (41) recognizes the bene- 
ficial effects of drying upon germination, but believes that germ- 
ripening or after-ripening is a process in general independent of 
seed-moisture content. He reports an elaborate series of tests 
under various conditions modifying germination, and concludes 
as regards oats that germ-ripening is a characteristic varying wit 
the strain tried. He discredits explanations of after-ripening oF 
germinative variations which are based on seed coat exclusions of 
water or gases, or on enzymatic alterations as so far set forth; yet 
believes that in some way enzymes are associated with germ 
ripening. 
2. GENERAL GERMINATION sTUDIES.—No attempt will be made 
to cite all the recent literature on the general field of germination 
- However, a few instances may be cited to show that such problems 
have been approached from at least three different angles: (1) 
studies of germination factors external to the embryo; (2) pont 
associated with chemical or physical alterations of members W1 
