The dark brown resinous mass that remained may be either an alcoholic resin formed through the hydrolysis of the ester resins or it may be a resin belonging to the class known as resenes[11] which resist saponification.

[11] Com. Organic Analysis. Allen Vol. II, 146.

METHYSTICIN AND METHYSTICINIC ACID.

The crystalline product obtained from the ether extract was recrystallized several times from absolute alcohol to remove all traces of any resinous material. It had a melting point of 122-123. It therefore was not pure methysticin, which has a melting point of 138-139 degrees. On examining this product under the microscope it was found to contain two distinct forms of crystals, long needles and prismatic plates. Some free methysticinic acid, melting point 180 was examined under the microscope and found to consist entirely of prismatic plates. Therefore the original crystalline body contains some methysticinic acid.

Some of the original precipitate was crystallized once from absolute alcohol and thoroughly dried. This was used for the following data to determine the percent of free methysticinic acid in the crystalline product. A weighed amount of the crystalline product was dissolved in carefully neutralized alcohol, and titrated with tenth normal NaOH, using phenolthalein as the indicator.

Wt. of substance used.2590
NaOH N/10.5 cc
% methysticinic acid.

The potassium salts of the various resin acids formed by the saponification of the ester resins should yield a resinous mass syrupy or oily in consistency when acidified, if it consists entirely of the two groups of acids spoken of as the iron acids and the barium acids. Also the weight of the barium acids plus the weight of the iron acids should nearly equal the weight of the ester resins, if these are the only two acids, because the alcohol radicals constitute not more than two percent of the ester resins. But when the total potassium salts were acidified the product formed contained a crystalline substance in addition to the resinous acids. This crystalline substance was separated from the resinous acids by means of their difference in solubility in ether. On recrystallization from absolute alcohol, it had a melting point of 179 degrees Centigrade. It is therefore methysticinic acid. This acid constitutes about twenty percent of the total acids from the ester resins because the barium and iron acids constitute only about seventy five percent.

This methysticinic acid cannot be entirely formed by hydrolysis of methysticin which was incompletely removed from the resinous material. The methysticinic acid existed either combined with some other alcohol than methyl alcohol or was combined with one of the resin alcohol radicals.

PHYSIOLOGICAL ACTION.

Due to the impossibility of preparing the alkali salts of the barium and iron acids so as to be positive that the resulting preparations completely represented the barium and iron acids, and due to the insolubility of the acids and the total resins in solvents from which they would not again be precipitated when introduced into the circulation, it was found necessary to make an emulsion. The emulsifying agent used was acacia (gum arabic). It was possible by careful preparation to make a permanent emulsion that was miscible with water in all proportions to form a homogeneous mixture. The animals used were rabbits of about six pounds weight. The injections were made by Dr. Geo. McCoy, director of the Leprosy Investigation Station at Kalihi. All the physiological experiments were made at the bacteriological laboratory at the Leprosy Investigation Station.