December i, 1889.] THE TROPICAL AtJRTCIILTU Rl ST. 
43 
Influences of Light upon the Sprouting of Seeds. — 
Verv great differences in results may sometimes be 
expected between samples exposed to light during the 
process of sprouting, and those kept in darkness. — 
When such differences occur, they indicate that light 
retards or even wholly prevents germination. — In some 
species this influence of light is greatly marked, while 
in others it is not apparent. — It is apparent that 
those apparatuses which test seeds by holding them 
on a porous plate above water, are to be looked up- 
on with distrust, uoless provided with an opaque cover- 
ing ; and even then they may prove unsatisfactory, 
as the experience with the Larkspur seeds indicates 
that best sproutings follow planting in the foil. 
Weight of Seed in Relation to Sproutino. — Variations 
in results of testing, both as regards rapidity of 
sprouting and the total amount, they may expected 
between seeds of different weights in the same sample. 
— This variation is much greater in some species 
than in others. In our tests the variation was parti- 
cularly marked in Cabbage, Radish, Sweet Pea, Bean, 
Gesse, (Lathyrus sativus), Burnet (Poterium sangui- 
sorba), Martynia, Orach. — As a rule, the heaviest 
seeds in any sample give earliest and highest results. 
— In some cases, the lightest seeds in the sample give 
earliest and highest results, apparently because the 
heaviest seeds, with which they are compared, are 
over-ripe ; or, in some instances, under-maturity may 
result in earlier germinations, and such seeds are 
sometimes light in weight. 
Colour of Seed in Relation to Sprouting. — Seeds which 
differ widely in colour in any sample frequently give 
different results under test. — This variation in results 
may lie in greater rapidity of sprouting, or in higher 
total amounts, or in both. — The relative values of 
seeds of different colours vary with each species, or some- 
times with each sample. 
Influences of Latitude upon the Sprouting of Seeds. 
— Northern grown corn appears to germinate more 
quickly than Southern grown corn. 
Variations in Duplicate Tests under Like Conditions. 
— One test cannot be accepted as a true measure of 
any sample of seeds. — Variation in duplicate tests is 
likely to be greater when seeds are planted in soil 
than when tested in sume sprouting apparatus like 
the Geneva tester. 
Comparisons of Results of Seed tests with Results of 
Actual Sowing in the Field. — The table indicates that 
ac'ual planting in the field gives fewer germinations 
than careful tests in conditions under control. This 
difference in total of germination, even under favour- 
able conditions of planting, may amount to over 50 
per cent. — In planting, due allowance should be made 
for the comparatively bungling methods of field 
practice by the use of greater quantities of seeds 
than would seem, from the results of tests, to be suffi- 
cient. 
General Summary. 
1. Variations in temperature may cause variations 
in rapidity of sprouting. 
2. An essentially constant temperature of about 
74° gives quicker results than an ordinary variable 
temperature of a similar mean. 
3. It is probable that aDy constant temperature 
gives quicker results than a variable temperature of 
which the mean is the same as the constant tem- 
perature. 
4. As the mean temperature lowers, sprouting, as 
a rule, becomes slower. 
5. In some instances, greater rapidity of sprouting 
due to a constant temperature of 74°, does uot ap- 
pear to be correlated with greater per cent, of total 
sprouti' g- I" Beans, however, greater per cent, of 
sprouting appears to follow greater rapidity of 
sprouting. 
6. There is probably a tolerably well-defined opti- 
mum temperature for each species of plant, in which 
best results from seed tests can be obtained. This 
limit is not closely determined for most garden 
seeds 
7. The quantity of water applied to seods may 
determino both the rapi ityand percent, of sprouting. 
8. A comparatively small amount of water gives 
quickeit and largest results. 
9. Greater quantities of water than are required 
for best results, lesson rapidity and per cent, of 
sprouting either by causing the seeds to rot, or by 
retarding germination, or by both. 
10. The soaking of seeds in water before planting 
does not appear to hasten sprouting, if the planting 
time is reckoned from the time at which the seeds 
are put to soak. But if planting time is counted 
from the time of placing the seeds in soil, quicker 
sproutings are the result ; this method of reckoning 
is incorrect, however. 
11. The soaking of seeds does not appear to influence 
the total amount of sprouting. 
12. The results of soaking appear to vary in dif- 
ferent species. 
13. The character of soil in which the test ia 
made may influence the results, both in rapidity and 
per cent, of sprouting. 
14. Light has great influence upon the sprouting 
of the seeds of some species. 
15. When light has any influence, it retards or 
wholly prevents sprouting. 
16. The effects of light upon sprouting are different 
in different species. 
17. The weight of the seed is often a tolerably 
accurate measure of its viability, as determined Loth 
by rapidity and per cent, of sprouting. 
18. As a rule, heavy seeds germinate better than 
light ones of the same sample. 
19. Seeds of different species may vary in sprout- 
ing in reference to weight. 
20. The colour of the seed in some cases is a 
tolerably accurate measure of rapidity and per cent, 
of sprouting. 
21. When there is any variation in viability in 
reference to colour, it is usually found that the 
stronger sproutings occur in the darker coloured seeds. 
22. The relative value of seeds of different colours 
varv with each species, or sometimes with each sample. 
23. The latitude in which seeds are grown may 
determine their behaviour in germination. 
24. Northern grown corn appears to germinate 
quicker than southern grown corn. It is to be ex- 
pected, from our knowledge of the variation of plants 
in reference to latitude, that seeds of most species 
will give similar results. 
25. Variation in results of seed-tests may be due 
to the apparatus in which test is made. 
26. Those apparatuses in which the seeds are ex- 
posed to light are to be " distrusted. 
27. Those apparatuses which afford no protection 
to the seeds other than a simple layer of cloth, pa- 
per, board, or similar cover, are usually unsafe, from 
the fact that they allow of too great extremes in 
amounts of moi-ture. 
28. The so-called Geneva tester appears to give 
better results of sprouting than tests made in soil, 
probably from the fact that moisture and temperature 
are less variable than in the soil tests. 
29. In order to study germination to its comple- 
tion, tests must be made in soil. 
30. Tests made indoors are more reliable than 
those made in the field. 
31. One test cannot be accepted as a true measure 
of any sample of seeds. 
I. The results of a seed-test depend very largely 
upon the known conditions under which the test is made. 
11. Results commonly vary between tests made 
under apparently identical conditions, even with se- 
lected seeds. Therefore — 
III. The results of actual ordinary planting in the 
field cannot be considered a true measure of the 
viability or value of any sample. 
IV. Rapidity of sproutings, unless under identical con- 
ditions, is not atrue measi-r -'of vitality or vigour of seeds 
V. There appears to Be no pernicious adulteration 
of garden seeds in this country, and, as a rule, the e 
a e 'O hurtful impurities 
In the ordinary farmer's garden seed-testing is 
perhaps of little or no value, but to the market gar- 
dei.er, who plants considerable areas to special crops, 
and to the seedsman, it is highly profitable. It is 
possible than in some cases the character of the crop 
can be prognosticated with some degree of certainty 
