Acknowledgements 



We are indebted to Dr. John H. Krickel, Director, Laboratory Training and Consultation 

 Division, Bureau of Laboratories, whose guidance, support, and encouragement made tiiis manual 



a reality. 



We gratefully acknowledge the assistance of our colleague Elliott Churchill, Writer-Editor, 

 formerly with the Bureau of Laboratories and currently with the Bureau of Epidemiology. Her 

 editorial expertise, patience, and sense of humor were invaluable. 



We are further indebted to Dr. Roslyn Q. Robinson, Director, Bureau of Laboratories, 

 Dr. Philip S. Brachman, Director, Bureau of Epidemiology, and many staff members from both 

 Bureaus whose cooperation and support were vital to the development of this manual. 



IV 



