INTRODUCTION. 15 



laboratory work was done by Dr. Elizabeth E. Clark, B. A. (Bryn Mawr), M.D. (Women's 

 Medical College of Philadelphia), who was well fitted for such an investigation by lier 

 training in the laboratories of these colleges, and who devoted two j'^ears to the investi- 

 gation. Dr. Clark made all of the studies recorded in Part II, with the exception of a group 

 including the studies of Vicia, Lathynts, Quercus, Castanea, Lilium, Tulipa, Convallaria, 

 Avmryllis, Crimim, Sprekelia, Hocvmnthus, Hymenocallis, Leucoium, Crocus, Sparaxis, Cur- 

 cuma, Maranta, and Zamia, and some incidental investigation here and there. Practically 

 all of the studies included in the latter group, and also the determinations of the tempera- 

 tures of (jelalinization, were made by Miss Martha Bunting, B. L. (Swarthmore) , Ph.D. 

 (Bryn Mawr), whose painstaking work in various laboratories is so well known to biolo- 

 gists as to render an introduction needless. The author has also received help from 

 Dr. Clark and Miss Bunting and other assistants in getting together the literature quoted, 

 and in other ways; and for three and a half years he has devoted to this research 

 all of the hours that could possibly be taken from the very exacting requirements of pro- 

 fessorial work. 



It goes without saying that, inasmuch as the author is not a botanist, the botanical 

 data given are based upon other and recognized authorities. Free use has been made of 

 the voluminous work of Engler and Prantl, Die Natiii'lichen Pflanzenfamilien, begun in 

 1889, but unfortunately still incomplete; of the Index Kewensis; of Warining's Systematic 

 Botany; and of many other standard authorities, especially of the admirable four-volume 

 Cyclopedia of American Horticulture by Bailey, which often has been followed quite closely. 

 The classification and nomenclature of plants are undergoing continual change, and it has 

 been puzzling at times how best to identify plants and to state relationships, but the 

 data of this character found at the heads of the various chapters have been based on the 

 highest authorities. The brief descriptive introductory notes on the different genera, 

 species, etc., will doubtless prove of value to many readers in refreshing their memories, 

 as well as in other ways. Altogether over 300 starches were studied, a goodly number, 

 but ridiculously small when one recalls to mind that the total known number of plant 

 species is over 230,000 (over half of which are Monocotyledones and Dicotylcdones) — ■ 

 not to speak of the thousands of varieties, hybrids, etc. Most of the material from which 

 the specimens were prepared was obtained from E. H. Krelage & Son, Haarlem, Holland; 

 James Veitch & Sons, London; Henry A. Dreer and Hemy F. Michell & Co., Philadelphia; 

 J. M. Thorburn & Co. and Peter Henderson & Co., New York; Bobbink & Atlcins, Ruther- 

 ford, New Jersey; and Reasoner Brothers, Oneco, Florida. Some were secured from or 

 through the Botanical Department of the University of Pennsylvania by the courtesy of 

 Prof. J. M. Macfarlane (to whom the author is indebted for help in many ways), and quite 

 a number from dealers and growers in various parts of the world. 



GENERAL CHARACTERS OF THE INVESTIGATION AND RECORDS. 



A glance through the pages of this memoir will be all that is necessary to convince 

 the reader of the superficiality and general crudeness of the investigation; and that the 

 records of the laboratory studies of the properties and differentiation of the various starches 

 are of a purely tentative character and therefore, for comparative purposes, in the nature 

 of merely temporary standards. It is obvious that if data are to be had that are to be 

 accepted as constants, certain absolutely essential conditions which have not been suffi- 

 ciently recognized in this work must be satisfied. As, for instance, every plant from which 

 starch is obtained must positively be identified botanically; the starch must be so pre- 

 pared as to eliminate, as far as possible, without injury to the molecule, all contaminating 

 substances; examinations should in every instance be made with two or more specimens 

 obtained from different plants of the same species; the influences of age, environment, and 



