126 APPENDIX. 



oil. At 15° 0. it has a sp. gr. of ;9270j at 38° 0. it forms an 

 emulsion and solidifies only below--5° 0. It is scai'cely soluble in 

 spirit of wine, and very sparingly in ether. Chemically, it consists of 

 25 parts stearin and 76 parts of oleiu. In China it is used as a table 

 and laaip oil and for the manufacture of soap, for which it is 

 specially well adapted, yielding a beautiful hard soap. 



Tea oil has been used in China for a very long time, but has been 

 only recently introduced into commerce. C. oleifera and C, drupifara 

 yield oil for household purposes similar to the above. (Branni.) 



Caffeine and Theine : their identity, and the reactions of 



Caffeine with Aurio Chloride. " 



In consequence of the conclusions of Mays {Journ. Physiol., 7, 458; 

 Therapeutic Gazette,\%Q^^ 587), and more recently of Lauder-Brunton 

 and Cash {Proc. Roy, Soc,, 42, 233 ; Joiirn. Physiol., 9, 112), that the 

 physiological action of theine obtained from tea differs in certain 

 respects from that of caffeine obtained from coffee, the authors have 

 searched for evidence of isomerism in these bases, the existence of 

 which is not put beyond doubt by the chemical comparison of them 

 which has hitherto been made. 



Having extracted theine from tea and caffeine from coffee, it is 

 shown that the two substances exactly resemble each other, and melt 

 at precisely the same temperature, vk., 234°-5 (corr.). Prom each 

 base the crystalline aurochloride (C*H'°N*0', HCl, Au CP2 H''0) 

 was prepared, and these two salts both melted at 242°-5 (corr.). 

 When dried at 100°, they both lost the equivalent of two molecular 

 proportions of water, and the anhydrous salts melted at the same 

 temperature, viz., 248''-5 (corr.). The analytical data corresponded 

 with the formulae given above. The complete correspondence in the 

 properties and composition of the aurochloride is satisfactory 

 evidence of the absence of a structural difference in the bases. lu 

 order to further confirm the identity of the two substances, a specimen 

 of each was converted into the mercuric chloride compound (O'H'" 



(5\ 



a stable crystalline salt. Both preparations were 



found to melt at the same temperature, viz., 246° (corr.), and to 

 exactly correspond with each other in other respects. 



The complete identity of caffeine and theine having thus been 

 demonstrated, the observed differences in their physiological action 

 must be ascribed either to impurities in the specimens used, or to 



