STUDY OF YUCCA ANGUSTIFOLIA 137 



By the above examination, this resin was thrown out of the 

 numerous classes of described resins. It is proposed to name 

 it yuccal. 1 



Yuccal was soluble in boiling absolute alcohol and acetic 

 ether; incompletely soluble in benzole, carbon di-sulphide, 

 alcoholic ammonia, and cold acetic ether. The red color of 

 the resin was removed by cold acetic ether, a transparent sub- 

 stance remaining, soluble in hot acetic ether. 2 Yuccal was 

 dissolved by potassio-mercuric iodide. It reduced aqueous 

 solutions of gold and platinum chlorides. A blood-red color 

 reaction was obtained by warming a small quantity of the 

 resin on a crucible lid with a crystal of ammonium molyb- 

 date and a few drops of nitric acid. On adding to the resin 

 mixture a few drops of strong sulphuric acid, and again warm- 

 ing, it was dissolved. Warm dilute nitric acid dissolved the 

 resin, colorless; cold nitric acid gave a brownish-green color 

 reaction. 3 Yuccal was heated on platinum foil, and as it de- 

 composed the fumes that were given off were pleasant and 

 aromatic. Tests failed to show the presence of benzoic or 

 cinnamic acids. 



1 I suggest that in future all resins be distinguished by the terminal syllable 

 al, for uniformity of resin nomenclature. "Yuccal," Science, September n, 

 1885, p. 210. 



2 I have examined the action of acetic ether as a solvent for resins. Cold acetic 

 ether dissolved ordinary resin, turpentine, styrax, tolu-balsam, mastic, elemi, 

 Canada-balsam, Peru-balsam, copaiba-balsam, Venice-turpentine, and, incom- 

 pletely, spruce-gum and yuccal. In hot acetic ether, spruce-gum and yuccal 

 were soluble. The following resins were insoluble in hot or cold acetic ether : 

 guiacum, sandarac, shellac, benzoin, olibanum, ammoniac, myrrh, galbanum, 

 and asafcetida. 



3 A reddish-yellow decomposition product resulted from the action of nitric 

 acid on many resins which followed generally quite soon after adding the 

 acid to a small quantity of the resin (o. i gram of the resin and 5 c. c. of nitric 

 acid, i.4sp. gr.). But the reaction which took place varied according to the 

 conditions, i. e., strength of acid used, the application of heat to the resin 

 acid mixture, or the addition of solvents to the mixture. The more concen- 

 trated the acid the more rapid was the reaction. The application of heat also 

 hastened the change, especially if a more dilute acid was used in the mix- 

 ture. Some solvents acted like heat by increasing the energy of the reactions. 

 Alcohol and ether were active solvents, and the reaction was attended by the 

 escape of nitrous fumes from the combination of alcohol or ether and nitric 

 acid. Chloroform and benzole were indifferent. Amyl alcohol acted feebly. 



