126 APPENDIX, 
oil, At 15°C. it has a sp. gr. of -9270; at 38°C. it forms an 
emulsion and solidifies only below—5° C. Itis scarcely soluble in 
spirit of wine, and very sparingly in ether, Chemically, it consists of 
25 parts stearin and 75 parts of olein. In China it is used as a table 
and lamp 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. drupifera 
yield oil for household purposes similar to the above, (Brannt.) 
Caffeine and Theine: their identity, and the reactions of 
affeine with Auric Chloride. 
In consequence of the conclusions of Mays (Journ. Physiol,, 7, 458; 
Therapeutic Gazette, 1866, 587), and more recently of Lauder-Brunton 
and Cash (Proc, Roy, Soe,, 42, 233; Journ. 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 a 
at precisely the same temperature, viz., 234°5 (corr.). From 
base the crystalline aurochloride (C°H*°N*O’, HCl, Au Cl*2 HC ‘ 
was prepared, and these two salts both melted at 242°-5 (corr.). 
When dried at 100°, they both lost the equivalent of two molecular 
Dae of water, and the anhydrous salts melted at the same 
temperature, viz., 248°-5 (corr,). The analytical data corresponded 
with the Soiuabe 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. In 
order to further confirm the identity of the two substances, a specimen 
of each was converted into the mercuric chloride compound (O°H?° 
N’*O?, HgCl’), 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 haying thus been 
demonstra‘ 
ted, the observed differences in their physiological action 
must be ascribed either to impurities in the specimens used, or to 
