﻿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 per 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 fi-om the 37 bales that over 16,000 live 

 larvae of the pink bollworm were being brought to the United States 

 each year, 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 necessary 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 by 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 hei-etofoi-e had been uncontrollable. It 

 Iherefore seemed possible that the vacuum process miglit be utilized 

 in the fumigation of bales of cotton without necessitating their 

 opening. A small experimental plant was established by the board 

 at AVashington 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 inij)oit('d lint cotton was pi-omnigated by the Secre- 

 tary of Agricnlture A[)ril 27, 1915, effective July 1, 1915, and a do- 

 mestic quarantine regulating the inovemcnt of cotton lint from the 

 Territory of Hawaii to the nniinland was i)roinulgate(l June 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 th« 

 screening of all i-oonis or buildings in which foi-cign cotton was kept 



