One of the most important factors contributing to maximum agricultural crop production per unit of land is the use of good seeds. Such seeds should have a high purity value, i.e. they should be free from all other seed types, whether of weeds or of cultivated plants, and their germination capacity and vigour should be high, thus providing the best possible guarantee of a good seedling stand – in spite of diseases, insects, competition of weeds, and unfavourable weather conditions. This fact has, of course, been recognized for a long time; but the systematic storage of seeds to maintain viability, and the routine testing and analysis of seeds for planting value, dates from only about the beginning of this century.