14 BTTLLEIIN/ 1465. U. S. DEPARTMENT OF AGEICtTLIUEE 
eye of the seed piece from a separate tube. The eves were always 
turned upward, so that they could be examined. Any contamina- 
tion which existed on the seed usually developed on the agar. There 
were many contaminations,, caused by the organisms present in 
deep folds of the epidermis about the eye. 
In another large number of cases where no contamination developed 
the eye had been so pared away that it failed to germinate. Both 
the contaminated and the nongerminating pieces were discarded. A 
period of two weeks to a month was required to determine finally 
whether a seed piece was going to germinate properly and was free from 
foreign organisms. The work of preparing the seed pieces was done 
in the culture house. The sterile and germinating seed pieces wei -:- 
planted in the cans in soil which had been tested and found to be 
sterile. 
PLANTING THE SEED PIECES 
A can from which a preliminary test sample of soil had been taken. 
through the water pipe in the cover and plated on soil-decoction agar 
and found to be sterile was taken into the culture house. There w 
also taken two or more jars containing sterile germinating seed pieces, 
the necessary tools, sterile tapes, glue, varnish, water, gasoline torches, 
lamp chimneys, and other necessities. The door of the house was closed, 
the interior sprayed, and the torches lighted. The entire cover and 
the upper part of the can were then given a drastic flaming with a 
gasoline torch. 
The hexagonal opening of the cover was first uncovered and a 
sample of soil taken in a sterile test tube. The wooden block shown 
in Figure 5 was drawn out and a sterile seed piece was taken from 
a jar and pushed down the hole left by the removal of the block. 
Care was taken always to arrange the seed piece so that the one bud 
was in an upright position and approximately under the hole in the 
center of the cover. Soil drawn away from beneath the hole in the 
center of the cover was pressed down about the seed piece, smoothed 
over, and well flamed with a blowtorch. The metal cover for the 
hexagonal opening was flamed, returned to place, and sealed again 
after many flamings. The opening at the center was now uncovered 
and well flamed. 
A lamp chimney was taken from a sack, the lower end dipped in 
il of sterile waterproof glue to the depth of an inch or more, and 
immediately set on the cover. The glue drained to the cover and 
effectually sealed the opening between the cover and the chimney. A 
very strong cotton cord was looped about the chimney above the 
bulge and tied as tightly as possible to the remnants of the cover 
handle. The details of this" arrangement may be observed in Plate 5. 
This completed the planting, and the can was ready to be placed 
in position out of doors for the summer. 
When a thermograph was to be attached to a can it was done 
the time of planting. The bulb and a sufficient length of wire were 
immersed in a 10 per cent solution of formalin for two hours and the 
bulb placed in the soil at the center of the can. The wire emerged 
at one corner of the hexagonal opening and was well flamed before 
being sealed in place. The joint was made tight with sterile tape, 
glue, and varnish, and no contamination was ever observed from the 
