1395.] Deviation in Development Due to the use of Unripe Seeds. 813 
seed is limited; some seeds will not grow after a few weeks or 
months, although most seeds are good for from one to several 
years. In all cases the seed gradually loses its vitality, and 
sooner or later ceases to live, unless in the mean time given 
the means for germination. 
In view of these facts we can better appreciate the importance 
of the discovery made by Cohn” that there is an optimum for 
most rapid germination which falls, as a rule, just before ob- 
vious maturity, (or possibly at the end of the resting stage, 
where this is very pronounced, a point not yet investigated), 
and before and after this optimum the germination is slower. 
We are thus led to consider the seed as accumulating energy 
up to the approximate time of its maturity, and then gradually 
losing this energy so long as it remains an inactive seed ; and 
that the measure of this energy is the vigor of its germination. 
There is a wealth of data to substantiate this theory of the life 
of a seed, but which would be burdensome to further present 
at this time. 
Turning now to a more detailed consideration of the devia- 
tions from normal development in plants from immature seed, 
the weakness of the seedlings will be one feature to first attract 
the attention of the investigator. In a number of trials with 
green seed of tomatoes, made at various times since 1889, I 
have found” that the young plants are under size; the stems 
being shorter and cotyledons smaller. They have less strength, 
and in consequence many perish in the vain attempt to lift the 
covering of soil. Some are unable to extricate the cotyledons 
from the ruptured testa, and often perish from this cause, even 
after having reached the light. If the seeds are germinated 
between folds of moist cloth or bibulous paper, such miscarriage 
will show even more clearly. Similar effects were observed by 
Cohn, in the use of canna seed. Hesays:* “All plants ob- 
** Ich selbst habe bei Canna, Œnothera, Lupinen und anderen ein mittleres 
Stadium im Reifungsprocesse beobachtet, in dem die Samen sich am schnellsten 
entwickelten; von da aufwiirts und abwiirts die reifen und die weniger ausgebild- 
eten schienen mir langsamer zu keimen. Cohn, Flora, xxxii, p. 504, 
23 The data are recorded in the manuscript records of the Indiana Experiment 
Station, and have not yet been published. 
% Dagegen waren alle aus den jüngsten Samen gezogenen Pfliinchen hinfällig 
und schwächlich und gediehen kaum über das erste Blatt. Flora, xxxii, p. 501. 
