[23] Jour. Chem. Soc. 71, 1194 (1897).

[24] Berichte 19, 1740.

[25] Ibid. 1747; Annalen, 112, 97.

[26] Biochem. Pflan. II, 521.

[27] Ann. de Chim. et de Phys., 6th Series, XXII, 76 (1891).

[28] Treatise on Chem., Vol. III, Pt. III, 492.

[29] Les Sucres; Chem. der Zuck.; Biochem. der Pflan.

[30] Chem. Zeit. 23, Rep. 177.

[31] Loc. cit. 1, 209.

[32] On standing several weeks, a small quant.i.ty of tar separated out on the walls of the vessel, also a brown precipitate which was filtered off, suspended in water, and hydrogen sulphide was being pa.s.sed in when an accident occurred and it was lost.

[33] "By warming with alkalies or barium hydroxide, rhamnose is colored yellow." Chem. der Zuck. I, 177.

[34] Ibid. 188.

[35] Ibid.

[36] Rayman, Sur L'Isodulcite, _Bull. Soc. Chim._ 47, 668 (1887).

[37] Acides Gummiques.

[38] Berichte XX, pp. 1089, 1091, 1188, 2566.

[39] Ann. de Chim. et de Phys. (6) XXII, 93 (1891).

[40] Biochem. der Pflan. I, 210.

[41] Comptes rendus CXV, 892.

[42] Amer. Chem. Jour. 28, 370.

[43] Amer. Jour. Pharm. 77, 255 (June, 1905); 78, 53 (Feb., 1906).

[44] A wax obtained from _Rhus succedanea_ was shown by Stahmer to contain palmitic acid and glycerol in the form of glycerol palmitate.

_Annalen_ 43, 343, (1842).

[45] See Amer. Jour. Pharm. 77, 256.

[46] This section is added in the hope that it may be of use to others who are subject to this form of poisoning.

[47] Moor, N. Y. Med. Rec. 45 (1894), 200.

[48] Bull. No. 26, U. S. Dept. Agr., Div. of Bot. 47.

[49] Lacerda, Comptes rendus 93 (1881) 466-469.

[50] Amer. Jour. Med. Sci. 52 (1866), 285.

SUMMARY.

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 poisonous tar or wax was decomposed by acids and yielded gallic acid, fisetin, and rhamnose, showing the probable source of these compounds in the plant, and indicating that the poison is a complex substance of a glucoside nature.

It was found that a portion of the poisonous substance could be precipitated by lead acetate from a solution of the purified tar in 50 per cent. alcohol.

All cases of poisoning developed on the writer were easily cured with pota.s.sium permanganate.

The following method is suggested for obtaining the poisonous substance from the plant: Extract the plant with alcohol, filter, and precipitate at once with lead acetate. Wash the precipitate, dry, and extract with ether in Soxhlet extractors (loosely filled). Combine the ether extracts, mix with water, and pa.s.s in hydrogen sulphide. Separate the water and the ether solution, and filter the latter. Wash the ether solution thoroughly by shaking with water, and then evaporate at a low temperature.

BIOGRAPHY.

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 graduate student in Chemistry, and was awarded one of the North Carolina Scholarships. His minor subjects are Physical Chemistry and Biology.