92 



SCIENCE. 



[Vol. XIV. No. 340 



be taught by the behavior of the seeds of species of Carex, 

 which were planted this spring. Of some eighty pots of seeds, 

 collected by Professor Bailey in Europe last year, thirteen show 

 germination at the present time ; and of these, all the most for- 

 ward, with two exceptions, are northern species, collected in Scot- 

 land. 



The conclusion is, that northern-grown corn appears to germi- 

 nate more quickly than southern-grown corn. 



IX. Variations in Duplicate Tests under Like Conditions. 

 It may be well to briefly call attention to the fact that scarcely 



any two tests made with seeds from the same sample, under con- 

 ditions apparently identical, are exactly alike in results. It fre- 

 quently happens that these results are so dissimilar as to give no 

 warrant for expressing an opinion of the value of a sample from 

 two or three tests. 



The conclusions are that (i) one test cannot be accepted as a 

 true measure of any sample of seeds ; and (2) variation in dupli- 

 cate tests is likely to be greater when seeds are planted in soil 

 than when tested in some sprouting apparatus like the Geneva 

 tester (cf. introduction to § III). 



X. Comparisons of Results of Seed-Tests with Results of 



Actual Sowing in the Field. 

 It has been said recently that the ideal test of seeds is actual 

 sowing in the field, inasmuch as the ultimate value of the seed is 



ined for impurities, and in ninety separate instances the results 

 have been tabulated and compared. This examination consisted 

 in counting every seed in the sample, counting the impurities, 

 weighing the seeds and the impurities, and determining, so far as 

 possible, the character of the impurities. The percentages of im- 

 purities, both by number and weight, have been calculated. From 

 these analyses it is easy to draw conclusions as to the probable ex- 

 tent of adulteration or impurity in garden-seeds. No- evidence of 

 adulteration was found, and weed-seeds were few and unimpor- 

 tant. In some cases the sample had not been properly cleaned, 

 but in general the more important seeds were very free from impur- 

 ities. The impurities were very largely immature and imperfect 

 seeds. The average of impurities, by number, was found to be 

 2.76 per cent, and by weight, 1.38 per cent. The investigation ap- 

 pears to indicate that there is no necessity for seed-control stations 

 in this country, for the purpose of preventing dishonesty and care- 

 lessness in the sale of garden-seeds. The detailed results will soon 

 appear in Agricultural Science. 



As a general summary of his results.^Professor Bailey gives the 

 following : — 



I. The results of a seed-test depend very largely upon the known 

 conditions under which the test is made. 



1. Variations in temperature may cause variations in rapidity of 

 sprouting. 



2. An essentially constant temperature of about 74° gives 



White Seeds. 



-Colored Seeds. 



its capability to produce crop. This notion of seed-tests is obvi- 

 ously fallacious, although the statement upon which it is based is 

 true : in other words, actual planting rarely gives a true measure 

 of the capabilities of all the seeds of any sample, because of the 

 impossibility to control conditions and methods in the field. The 

 object of seed-tests is to determine how many seeds are viable, and 

 what is their relative vigor. If planting shows poorer results, be- 

 cause of covering too deeply or too shallow, by exposing to great 

 extremes of temperature or moisture, or a score of other untoward 

 conditions, the sample cannot be held to account for the short- 

 coming. 



Various samples were tested indoors, and actually planted in the 

 field. The seeds were sown in the field June 5, and the last notes 

 were taken from them July 5. They were sown on a gravelly 

 knoll. Rain fell about every alternate day, and the soil was in 

 good condition for germination throughout the month. The in- 

 door tests were made in loose potting earth, or in sand in seed- 

 pans. 



The conclusions were, that (i) actual planting in the field gives 

 fewer germinations than careful tests in conditions under control 

 (this difference in total of germination, even under favorable con- 

 ditions of planting, may amount to over 50 per cent); and (2) 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. 



XI. Impurities in Samples of Garden-Seeds. 



Over one hundred packages of seeds have been carefully exam- 



quicker results than an ordinarily variable temperature of a similar 

 mean. 



3. It is probable that any constant temperature gives quicker re- 

 sults than a variable temperature of which the mean is the same as 

 the constant temperature. 



4. As the mean temperature lowers, sprouting, as a rule, becomes 

 slower. 



5. In some instances, greater rapidity ot sprouting, due to a 

 constant temperature of 74°, does not appear tj be correlated 

 with greater per cent of total sprouting. In beans, however, 

 greater per cent of sprouting appears to follow greater rapidity of 

 sprouting. 



6. There is probably a tolerably well defined optimum tempera- 

 ture for each species of plant, in which best results from seed-tests 

 can be obtained. This limit is not clos'=lv determined for most 

 garden-seeds. 



7. The quantity of water applied to seeds may determine both 

 the rapidity and per cent of sprouting. 



8. A comparatively small amount of water gives quickest and 

 largest results. 



9. Greater quantities of water than are required for best results 

 lessen 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 ap- 

 pear 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. 



