74 Weeds. 



expenditure of labor, we must study the 

 habits of that weed as affected by the con- 

 ditions under which it grows. Under some 

 conditions, ordinary "good farming" will 

 generally banish a weed ; while under oth- 

 ers "specific methods," energetically and 

 persistently applied, will be absolutely 

 necessary. It is apparent, therefore, that 

 for the destruction of weeds hard and fast 

 rules that will be equally applicable under 

 all circumstances cannot be laid down, for 

 what would be a proper course to pursue 

 under some conditions may be wholly unfit 

 under others. 



4. Sozv only clean seed. Where farms 

 are to be made clean, and to be kept so, 

 great care should be exercised in the pur- 

 chase of seeds, and also in the preparation 

 for the sowing of those grown at home. The 

 distribution of weeds is more widely effected 

 through the agency of the seeds sown for 

 useful crops than in any other way, as was 

 shown in Chapter IV. It has, doubtless, 

 been through this agency that nearly all 

 our foreign weeds have been brought to 

 our land. It is not enough for the seeds- 

 man to assure us that his seeds are clean, 

 for he may be deceived himself. If his 



