I.] SEED TESTING 17 



destroyed at the temperature of drying, so that when the 

 malt is afterwards ground and extracted with water — the 

 mashing process — there is sufficient diastase to convert 

 quickly all the starch of the endosperm into sugar, which 

 is afterwards fermented by the yeast into alcohol. 



Having thus considered the factors that determine 

 the germination of seeds, we are in a position to consider 

 the application of them to practice. In the first place, 

 the seed must be alive ; it must not have begun to 

 sprout and then been dried off again ; it must not have 

 been overheated in the stack, or harvested prematurely 

 before the embryo had come to its full term ; it should 

 not be so old as to have declined in vitality. It is easy 

 to make a germination test of the common farm or 

 garden seeds; select a soft tile, and with a file score 

 ten parallel grooves across it, then ten more crossing 

 them at right angles, thus giving rise to 100 points of 

 intersection. Stand the tile in a dish of water so that 

 the scored surface is above the water but is kept damp 

 by the porous nature of the tile, and set out 100 of the 

 seeds taken at random, one on each intersection. Cover 

 over with another plate or dish, set it in a warm place 

 and examine every day, counting the number that have 

 started, and removing them. A saucer of fine sand or 

 even three or four thicknesses of blotting paper will do 

 as well as the tile, though the water supply may require 

 a little more attentioa Most farm seeds will have ger- 

 minated in ten days, but mangolds require a fortnight, 

 and the majority of grass seeds three weeks. If the 

 records are properly kept, a table is finally obtained which 

 shows both the percentage which eventually germinate 

 and the rapidity with which they start; with a good 

 young vigorous sample, most of the seeds start within 

 a day or two of one another and comparatively early. 



Given good seed, it is of no use tn sow it until the 



B 



