THE PINK BOLLWORM 17 
the roller and the knife through small openings caused by wear. 
The waste from 37 bales which was examined showed sound seeds, 
some of them infested, varying from 27 to 600 per bale. The 
average j:>er bale was 215. The variation in the different bales de- 
pended upon the grade of the cotton, the lower grades having many 
more seeds than the better ones. It was estimated on the basis of 
the examination of waste from the 37 bales that over 16,000 live 
larvae of the pink bollworm were being brought to the United States 
each } T ear, of which several hundred went to the mills in the Cotton 
Belt, 
It thus became evident that a quarantine which did not take into 
consideration the seeds in bales of lint was inadequate. Conse- 
quently in May, 1914, a public hearing was held to discuss various 
means of protection. The different proposals made were that foreign 
cotton be excluded altogether from the United States; that it be 
admitted only under a guaranty that all seeds had been eliminated, 
or that the cotton had been disinfected; that it be allowed to proceed 
only to mills outside of the Cotton Belt; and that it be sent to 
southern cotton mills only after a period of storage of 18 months or 
more in northern localities. At the public hearing, and subsequently 
through conferences with members of the cotton trade and repre- 
sentatives of manufacturing associations whose assistance was very 
valuable to the department, it became evident that there were in- 
superable obstacles in the way of any of the plans mentioned. It 
therefore became necessaiy to make an exhaustive study of the 
possibility of destroying any infestation which might be found in 
the bales of lint. The use of cold was found to be impracticable. 
The use of heat was also impracticable on account of the time neces- 
sary to penetrate the highly compressed bales of Egyptian cotton 
and on account of the increased danger from fires when bales which 
had been heated were opened in the mills. 
About this time E. R. Sasscer, of the Federal Horticultural 
Board, and Lon A. Hawkins, of the Bureau of Plant Industry, had 
been conducting some experiments in the destruction of insects in 
various plant products b}^ fumigation in a vacuum. It was found 
that the killing power of hydrocyanic-acid gas was increased enor- 
mously in vacuum and it thus became possible to reach certain 
classes of insects which heretofore had been uncontrollable. It 
therefore seemed possible that the vacuum process might be utilized 
in the fumigation of bales of cotton without necessitating their 
opening. A small experimental plant was established by the board 
at Washington and a long and what turned out to be a most 
interesting series of experiments was begun by Sasscer. 
While this investigation was in progress an order regulating 
the entry of all imported lint cotton was promulgated by the Secre- 
tary of Agriculture April 27, 1915, effective July 1, 1915. and a do- 
mestic quarantine regulating the movement of cotton lint from the 
Territory of Hawaii to the mainland was promulgated dune 11, 
1915, effective on and after July 1, 1915. Under this order and 
quarantine, tentative regulations were issued governing and re- 
stricting the entry of foreign cotton and also providing for the 
screening of all rooms or buildings in which foreign cotton was kept 
