188 TRANSACTIONS AND PIIOCEEUINGS OF THE [Sess. lv. 



varnish." It is mentioned that Sonora gum is used in the 

 manufacture of porter by brewers in California. 



An account of some of its chemical reactions is given by 

 Grazer.* Stillmannt has noted that the lac of Larrea 

 contains more dye (Farbstofi') than that of the Acacia, and 

 considers it very probable that the Arizona shellac has the 

 same chemical constitution as the Indian product. His 

 analysis of Arizona shellac is as follows : — 



Kesin and other bodies soluble in alcohol, . 

 Colour substance dissolved out with water, 

 Lac soluble iu caustic potash, . 

 Insoluble residue, ..... 

 Loss, and colour substance dissolved out in 



caustic potash, . . . . . 4*6 ,, 



A description of Acacia Grcggii, Gray, the Cat's-claw 

 Mesquit, is given by Eothrock,| but no mention is made of 

 its having exudation at any point. The peculiarities of 

 L. mexicana,^ however, are thus noticed by him : — ■ 

 " Creosote-bush. Common form from Western Texas to 

 Kern County, California, and southward into Mexico. Dr 

 Loew's examination proves that ' the reddish-brown exudate 

 on the branches ' will yield a red colouring-matter showing 

 all the reactions of cochineal. ' The alcoholic extract of the 

 leaves on evaporation yields a greenish-brown residue of a 

 specific and somewhat disagreeable odour, more strongly 

 perceptible on boiling the extract with water. This residue 

 is only to a small extent soluble in water, and the solution 

 has an acid reaction. It yields a light yellow precipitate 

 with acetate of lead. . The part of the alcoholic extract that 

 is insoluble in water is easily soluble in alkalies. It also 

 dissolves in nitric acid at a moderate heat, whereby oxida- 

 tion takes place. On addition of water, a yellow brittle 

 mass is precipitated.' The Mexicans are said to use an 

 infusion of the leaves for bathing in, in rlieumatic affec- 

 tions." 



* Pharm. Journ., 3rd ser., vol. xvi. p. 128. 

 + Vide Botanischer Jahresbericlit, viii. i. p. 434. 



t Wheeler's Report, U.S. Geogrupli. Surveys West of the 100 Meridian, 

 vol. vi. p. 108. 



§ Ibid., pp. 41, 80. 



