TESTING OF SEEDS. 277 



1. The object aimed at in seed-testing is the determination 

 of the degree of genuineness, purity, and soundness of aver- 

 age samples. The examination, if thorough, should afford a 

 fair basis upon which an opinion of the commercial value of 

 the seeds may be reasonably based. It is to be observed at 

 the very outset, however, that there are certain possible 

 sources of error in such examinations ; for instance, the sam- 

 ples may not fairly represent the bulk of the seed ; but the 

 chances for doubt as to the validity of the estimates will be 

 diminished in number as the methods become more familiar. 



The selection of the sample must be made with great care. 

 In large lots of seeds, the samples must represent thorough 

 mixtures of the bulk; otherwise any examination would be 

 liable to unfairness, and surely lead to prejudices against the 

 process of testing. 



The weights of samples recommended at T'harand are as 

 follows : — 



For white clover and the fodder grasses . . 50 grams 



red clover, buckwheat 100 " 



the larger seeds ...... 250 " 



which may be closely enough represented by two, four, and 

 eight ounces respectively, as has been done by the Connecti- 

 cut Station. 



The Estimation of the Genuirieness and Purity. — This must 

 be by a careful examination, under a lens, of small amounts, 

 say of one hundred or two hundred seeds, taken from differ- 

 ent parts of the sample. Specimen sets of the more common 

 seeds of the garden and the farm, and of the weeds which 

 are found most frequently in admixture, are now procurable 

 in Europe, and are very convenient for reference by any one. 

 Not only the amount of impurities (wliich may be inorganic 

 as well as in the form of unwished-for seeds), but their nature, 

 should be examined. Although there are on record some 

 very surprising cases of careless or fraudulent admixture of 

 foreign matters in seed, the general residts of the examina- 

 tions abroad and at home are rather encouraging. 



