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 C

Acides Gummiques, Garros (Dissertation) 1895. American Chemical Journal. American Journal of the Medical Sciences. American Journal of Pharmacy. Annalen der Chemie und der Pharmacie (Liebig). Annales de Chimie et de Physique. Berichte der deutschen chemischen Gesellschaft. Biochemie der Pflanzen (Czapek) 1905. Brooklyn Medical Journal. Bulletin de la Société Chimique. Bulletins 20 and 26 U. S. Department of Agriculture, Division of Botany. Chemie der Zuckerarten, Von Lippmann, 1904. Chemiker-Zei

Plants belonging to the natural order Anacardiaciæ (Cashew family or Sumach family) are found in all the temperate climates of the world and quite frequently in semi-tropical climates. Many of these plants play important parts in economic botany, yielding dye-stuffs, tanning material, wax, varnish, and drugs. Several species are poisonous. At least three poisonous species of the genus Rhus are found in the United States. These three are all common and well-known plants, but confusion frequently

By far the most valuable work on Rhus toxicodendron is that of Pfaff. From a clinical study of Rhus poisoning, Pfaff came to the conclusion that the poison must be a non-volatile skin irritant. The more volatile the irritant, the quicker is its action on the skin. Formic acid acts very quickly; acetic acid, less volatile than formic, acts more slowly, but still much more quickly than poison ivy, the latent period of which is usually from two to five days. Pfaff thought that the volatile acid obt

An alcoholic solution of the resin was just neutralized with potassium hydroxide. During the titration, the solution rapidly became dark brown. After neutralization it was shaken with ether; the water solution remained brown while the ether layer was nearly colorless and contained practically no dissolved substance. A portion of the water solution of the potassium salt on being acidified with sulphuric acid and standing over night, deposited a slight precipitate. The solution of the potassium sa

Having identified gallic acid, and not finding any other phenol derivative in the lead precipitate, some of the original material was extracted with hot water to remove gallic acid and filtered from tar while hot. The filtrate had a deep yellow color. On cooling over night, an olive green precipitate separated out which was dried and found to be a light powder. It was practically insoluble in cold water, soluble with great difficulty in boiling water from which it separated in yellow flakes, sli

It was stated above that Schmid obtained a sugar solution by the decomposition of a fisetin-glucoside from Rhus cotinus , and Perkin obtained the same from a glucoside in Rhus rhodanthema . These investigators thought that the sugar was isodulcite or rhamnose, but they did not isolate it on account of the small quantities of material at their disposal. Moreover, the sugar is very hard to crystallize in the presence of other soluble substances and is not found in large quantity in plants. Maquenn

288 grams of the original poisonous material were extracted with 50 per cent. alcohol, and this alcoholic solution was precipitated with lead acetate in the manner already described (p. 17). The lead precipitate so obtained was extracted with ether in Soxhlet extractors and after the extraction was found by test to be free from poison. Therefore the poison, if precipitated by the lead acetate, must have been extracted by the ether. This ether solution had a dark green color, and was acid from ac

In the early stages of this work some experiments were made to see if potassium permanganate could be used to purify the lead precipitate by oxidizing the tar brought down in precipitation. It was found that the permanganate attacked the lead precipitate as well as the other organic matter in the vessel. This fact and the well-known value of permanganate in treating skin diseases, its use as an antidote for some kinds of alkaloid poisoning, [47] as an antidote given to cattle poisoned by plants,

Leaves and flowers of the poison ivy plant were extracted with ether and the ether was removed by evaporation. In the residue, the following substances were found and studied: gallic acid, fisetin, the sugar rhamnose, and a poisonous tar, gum, or wax. The lead compound of the poison was soluble in ether; this fact gave a means of separating the poisonous substance from the non-poisonous matter in one operation. The poison was not volatile with vapor of acetic acid, or with vapor of alcohol. The

William Anderson Syme, the author of this dissertation, was born in Raleigh, N. C., on July 11, 1879. He was prepared for college at the Raleigh Male Academy, entered the North Carolina College of Agriculture and Mechanic Arts in 1896, and was graduated in 1899 with the degree B. S. He was an Instructor in Chemistry at the same College from January 1st, 1900, until June, 1903, when he received the degree M. S. for graduate work. In October following, he entered Johns Hopkins University as a grad