THE TOBACCO BEETLE. 67 
Under laboratory conditions tests made with a Rontgen-ray tube 
permitting a high-energy input and giving an intense and powertul 
radiation produced results which promise that the X-ray process may 
be used successfully in treatment of cigars or tobacco infested with 
the tobacco or cigarette beetle. 
Heavy dosages must be given, as is indicated by the results of 
exposures given in several series of experiments. 
In treatment of the egg stage, heavier exposures are required to 
sterilize eggs which are near the hatching point than are required to 
sterilize eggs newly laid. 
In experiments performed by the ree a dosage cou lpne to 
150 milliampere minutes exposure with a spark gap of 5.5 inches 
gave satisfactory results with eggs in tobacco placed 7.5 inches from 
the focal spot of the tube. With this exposure the eggs in which 
embryonic development was well advanced hatched, but in all cases 
where these larvee were kept under observation they failed to reach 
the adult stage. 
The minimum lethal dosage at a given distance from the focal spot 
of the Rontgen tube used was not determined. 
In two separate experiments adults were given an exposure of 
600 milliampere minutes (amperage X time), with a spark gap of 
5.5 inches, giving an approximate voltage of 65,000. The distance 
from the focal spot of the Réntgen tube was 7.5 inches. The results 
were as follows: 
(1) No effect on length of life was apparent, as the beetles diéd 
at about the same rate as the same number of beetles kept as check. 
(2) Large numbers of eggs were deposited after exposure. These 
eggs were infertile. Eggs iid by the check beetles hatched normally. 
Larvee were given an exposure of 600 milliampere minutes, other 
conditions of the experiment being the same as in the eo ne 
with adults given above. While no immediate effect was apparent 
the treatment had the effect of stopping activity and development, 
the larvee remaining in a dormant condition for a prolonged period. 
All treated larvee died before reaching the pupa stage. : 
Two methods of treating cigars in factories with the X-ray proc- 
ess are employed at the present time. In one method the finished 
cigars in closed boxes are conveyed by a belt very slowly through 
an exposure chamber containing the Réntgen tubes. The walls of the 
exposure chamber are constructed of thick sheets of lead (lead is not 
penetrated by the Rontgen rays) in order to Bretees the operator 
of the machine from injury. 
In the other method of treatment a large room used as a humidor 
at the factory was completely lined with sheet lead. In a narrow 
compartment within the humidor, extending along one side, a 
series of 16 powerful Roéntgen-ray ones are arranged in two lines 
