SEED GERMINATION 
173 
the diagram. (Fig. 128.) This incubator is merely two 
boxes lined with wet sawdust and covered with wet burlap 
to hold the moisture. A temperature of eighty degrees F. 
should be maintained by placing the box near a stove or 
furnace. 
The corn should be allowed to remain in the tester for 
six or eight days if the temperature is low. After unroll¬ 
ing the doll, the rows of seedlings may be checked with 
Fig. 127.—Grain placed in a rag doll. The rows in the doll correspond to the 
number of the ear from which the grains are taken. 
the corresponding ears of corn. Those ears showing weak 
germination, or dead kernels should be discarded. 
Cotton.—A similar test may be made for seed cotton, 
with the exception that a check cannot be made of the 
plant unit from which the seed came. Weak seeds may 
be discarded by this method. Cloth used in making the 
test may be used again if boiled to destroy molds. If 
the rag doll is properly used it is perhaps the most effec¬ 
tive method of detecting weak or diseased seed. 
Wheat, Oats, and Clovers.—Seed of these crops may 
