viii Acknowledgments 



Many persons acquainted with the life and work of Dr. Smith 

 have been interviewed by the author. They include various of his 

 laboratory scientific associates and assistants and many scientists 

 in different research fields from the Atlantic to Pacific coasts, their 

 work or collaboration being described fully or in part in the 

 narrative. 



In the preparation of this book, valuable criticisms and sug- 

 gestions for improving the text have been given by Dr. L. O. 

 Kunkel, Research Member Emeritus and formerly head of plant 

 science research of the Department of Animal and Plant Pathology 

 of the Rockefeller Institute for Medical Research, New York City, 

 by Dr. H. L. Russell, Dean Emeritus of the College of Agriculture 

 of the University of Wisconsin, and by Mrs. Smith. They have 

 read the complete text in first writing. Dr. Conway Zirkle, Pro- 

 fessor of Botany of the University of Pennsylvania, has read the 

 text in a later writing. Substantial portions, especially part or 

 all of Chapters XI and XII, have been read by Mrs. Margaret 

 Reed Lewis, cancer research specialist, the Wistar Institute of 

 Anatomy and Biology, and by Dr. A. J. Riker, Professor of Plant 

 Pathology, of the University of Wisconsin. To each one, for very 

 helpful aid and advice, corrections, and new sources of knowl- 

 edge, the author wishes to express his cordial thanks and grateful 

 appreciation. 



