The author desires to avail himself of this opportunity to tender his
thanks to those under whose guidance he has worked while a student at
the Johns Hopkins University, namely to Professors Remsen, Morse, Jones,
and Andrews, and to Doctors Acree and Tingle for instruction in lecture
room and laboratory.
He is especially indebted to Dr. S. F. Acree, at whose suggestion this
research work was undertaken, for counsel and assistance in its
prosecution.
He would also thank Messrs. Parke, Davis and Co., of Detroit, Mich., for
the preparation of the crude material used in this investigation, and
the U. S. Department of Agriculture, Washington, D. C., for electrotypes
of figures 17, 18, and 19 in Bulletin No. 20, Division of Botany.