outstanding cooperation displayed by the many private concerns, agencies, and persons who submitted 

 compounds for testing. In the further use which we made of their samples in our study, we frequently 

 required additional chemical data or supplemental supplies of many compounds. These were kindly 

 provided by the contributors wherever it was possible for them to do so. We particularly appreciate their 

 generosity in permitting the chemical identification of most of their materials in this report. 



All rainbow trout and most of the bluegill sunfish fingerlings used in our tests were provided 

 by the Fish Division of the Michigan Conservation Department. Over 40,000 of these fishes were 

 delivered by the Department to our laboratory in small, periodic consignments. Mr. M. J. DeBoer, 

 Supervisor of Hatchery Operations for the Fish Division, was largely responsible for coordinating delivery 

 of the fish. His assistance, and that of other hatchery personnel of die Department, is gratefully 

 acknowledged. 



In addition to these specimens, one consignment of bluegill sunfish fingerlings was received 

 by us from the Rochester (Indiana) Fish Cultural Station of the Fish and Wildlife Service. 



Dr. James W. Moffett, Chief of the Service's Great Lakes Fishery Investigations, participated 

 in the planning of the investigation and contributed much administrative assistance which expedited our 

 work. Mr. John F. LesVeaux of the Research Department of the Niagara Chemical Division, Food Machinery 

 and Chemical Corporation, provided valuable technical advice, consolation, and suggestions concerning 

 methods of reporting our data. 



During the extended period the screening program was underway, numerous technical and 

 clerical assistants joined our staff for varying periods of time. Among those who demonstrated exceptional 

 interest and initiative in their duties were: Clifford L. Brynildson, Clyde O. Barr, Chester J. Pszczolkowski, 

 Rose L. Hoffman, Norma J. DeMara, Mary E. Dimick, Clarence H. Barrette, Clifford R. Kortman, and 

 Margaret A. Evans. The manuscript and tables for this report were typewritten for direct reproduction by 

 Martha A. Bergen. Many other persons, not associated with our staff, contributed advice and assistance 

 which were of material aid in the investigation. 



