William Anderson Syme

“ The presence of free gallic acid, fisetin, and rhamnose in the plant can be readily explained by a series of assumptions for which there is a considerable amount of experimental evidence. There is reason to believe that tannin-like bodies are formed at the expense of chlorophyll, [41] that complex tannin bodies can be broken down by acetic acid (also found in Rhus toxicodendron) into a tannic acid and a glucoside (for example, the "fustin-tannide" mentioned above yields tannic acid and fisetin-glucoside) ”

“ It was then thought that perhaps the oil could be converted into an ester which might be more volatile and could be distilled out. 20 grams of the original material were dissolved in 100 cc. of absolute alcohol containing 3 grains of hydrochloric acid gas, and the mixture was heated 10 hours on a water-bath under a return condenser. After the heating, the mixture had a delightful ethereal odor. ”

“ The difficulty of getting the remedy in contact with the poison in the skin is the reason why the eruption is hard to cure.
The remedy most commonly used for this eruption is an alcoholic solution of lead acetate. This remedy is unsatisfactory for the reason that its action consists in depositing an unstable lead compound of the poison in the skin where the conditions of moisture and temperature are favorable for its decomposition, liberating the poison with all its irritant properties. ”

“ After a long extraction of the lead precipitate in the Soxhlet extractors, the green ether solutions were combined and washed by shaking them with water to remove lead acetate and acetic acid in case any should have been held in the lead precipitate. The ether was distilled off at a low temperature and there remained a soft tar, a portion of which was not completely soluble in 95 per cent. alcohol. The alcoholic solution had a greenish yellow color and was poisonous. The tar was also partly soluble in acetic acid, and this solution was found to contain lead. ”

“ It is also conceivable that a volatile poison manufactured by a living plant could become non-volatile by changes in it consequent upon the death of the plant.
Up to the present time, only three important chemical investigations of the active principle of Rhus toxicodendron have appeared in medical and chemical literature, these being the researches of Dr. J. Khittel, J. M. Maisch, a pharmacist, and Dr. Franz Pfaff, of the Harvard University Medical School, to whose work reference has been frequently made. ”

“ The yield was increased by acidulating the mixture with sulphuric acid before the distillation. The acid distillate so obtained was freed from a non-poisonous oily substance by shaking the solution with ether. Barium and sodium salts were made by neutralizing the acid, and were purified by crystallization. Analysis showed them to be salts of acetic acid, and they gave the characteristic tests for this acid. The toxicodendric acid of Maisch was thus shown to be acetic acid, and was therefore not the poisonous principle of the plant. ”

“ The reaction with ferric chloride observed whenever a lead compound of the poison is decomposed by hydrogen sulphide may be explained by the formation of traces of gallic acid or fisetin through the action of the weak acids present.
The supply of purified poisonous tar having been exhausted in the preceding experiments, further study of the active principle is postponed until more can be prepared. It is highly desirable to investigate the white precipitate formed by addition of sulphuric acid to an alcoholic solution of the toxicodendrin. ”

“ With the knowledge of the facts mentioned, many solutions were tested for poison by applying them to the skin, and when an eruption appeared, it was cured quickly and permanently by rubbing in a permanganate solution, usually mixed with dilute sulphuric acid. ”

“ The presence of other plant [Pg 19] substances in the solution also interferes with the color tests, and finally, a substance which gives a blue color with iron salts and one giving a green color may be found together in the same plant. [19] Further tests with a solution of the resin in dilute alcohol, and with a water solution of the acid precipitated by adding sulphuric acid to a solution of the resin in potassium hydroxide, led to the conclusion that the acid is gallic acid. ”

“ He found that it was not volatile, was decomposed by heat, was soluble in alcohol, ether, chloroform, benzene, etc., but insoluble in water. Its effects upon the human skin were studied in many experiments upon himself and others. It was shown that an exceedingly minute quantity of the poison will produce the dermatitis, even 1/1000 milligram applied in olive oil being active. The oil was given internally to rabbits, its effects being most marked on the kidneys.
The oil obtained by Pfaff from Rhus venenata seemed to be identical with that from Rhus toxicodendron. ”

“ Nitrogenous ferments which can effect the hydrolysis of glucosides and give rise to sugars are frequently found in plants, for example, emulsin in almonds, myrosin in mustard, and erythrozym in madder. ”

“ Eleven and one-half grams of the resin obtained from lead precipitate A by decomposition with hydrogen sulphide were treated with 0.1 n. potassium hydroxide added from a burette until the acid was exactly neutralized. All went into solution. [Pg 20] On shaking with ether, some of the potassium salt separated out and was saved for examination. The solution became brown on exposure to air and got darker as the work proceeded. The acid in solution as a potassium salt was precipitated out in four fractions by adding for each fraction one-fourth the amount of 0.1 n. ”

“ 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. ”