58 
BULLETIN 1374, U. S. DEPARTMENT OF AGRICULTURE 
The live-steam machine was found under practical working con- 
ditions to have a capacity of 5 bushels per minute and required not 
more than two horsepower. The cost of operation was about the 
same as in the case oi the dry-heat machine. 
Continuous series of germination tests were made during the 
operation of these machines. There were no indications of any 
appreciable reduction in the vitality of the seed. 
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Fig. 14.— Number of infested cotton blooms per acre in poisoned and check plats, 1921 experiments, 
as shown by weekly examinations. First examination made six days after treatment began 
POISONING EXPERIMENTS 
The habits of the newly hatched pink bollworm larva suggest that 
there may be an opportunity to kill it by means of poison before 
it enters the boll or while it is attempting to enter. Experiments 
were instituted at Tlahualilo to determine whether any degree of 
control could be attained by dusting with arsenical poisons. 
In 1921, nine separate plats in Targe cotton fields were treated, 
seven of these with calcium arsenate and two with arsenite of zinc. 
Records were kept at the same time on an equal number of check 
plats of equal size. As the purpose of these first experiments was 
to determine whether any control could be attained, no attempt was 
