522 Scientific Intelligence. 



at 95 -96°, is easily soluble in chloroform and acetic oxide, spar- 

 ingly in absolute alcohol, insoluble in ether. It gives no reaction 

 for cholesterin and is not altered by acetic oxide or canstic alkali 

 even on iusion. By heating with 45 per cent hydrogen bromide 

 to 210° or 220°, it gives a bromide melting at S5 -87°, contain- 

 ing 14-5 per cent bromine. On treatment with potassium hydrox- 

 ide all the bromine is removed. — Zeitschr. physiol. Chem., xvii, 

 425 ; JBer. Berl. Chem. Ges. (Ref.), xxvi, 100, Feb. 1893. g. f. b. 



4. On the Identity of Caffeine and Theine. — Although caf- 

 feine was first isolated from, coffee in 1821 and theine from tea in 

 1827, their chemical identity has only now been established by 

 the researches of Dunstan and Shepheakd. Although this 

 identity seems never to have been questioned on chemical grounds, 

 yet the physiological action of the two seemed to indicate an 

 isomerism between caffeine and theine. The caffeine used in the 

 investigation was prepared from the unroasted coffee berries, by 

 extracting with boiling water, evaporating to a small bulk, mix- 

 ing with lime, drying on the water bath, and treating with boil- 

 ing alcohol. After removing the alcohol, the residue was dissolved 

 in one per cent sulphuric acid, filtered, treated with ammonia, and 

 the caffeine extracted with chloroform. Repeated recrystallization 

 from water gave silky needles fusing constantly at 234*5°. The 

 theine was prepared similarly from tea. It crystallized also in 

 silky needles fusing at 234-5°. To confirm this supposition of 

 their identity, both bases were converted into aurochlorides and 

 into mercurochlorides. When caffeine hydrochloride and auric 

 chloride are mixed together the aurochloride separates on cooling 

 in orange needles. The two aurochlorides appeared identical, 

 fused at 242-5° and 243°, lost at 100° 6-3 per cent of water, and 

 the anhydrous salt fused at 248-5°. The mercuro-chlorides also 

 appeared identical, the pure salt made from theine as well as that 

 made from caffeine fusing at 246°. The authors conclude there- 

 fore that there is no chemical ground for supposing caffeine and 

 theine to be structurally isomeric. Several new gold compounds 

 of caffeine are described in the paper. — J. Chem. Soc, lxiii, 195, 

 February, 1893. G. F. b. 



5. Lehrouch der allgemeinen Chemie ; von W. Ostwald. lite 

 Auflaue. Band I, 1163 pp.; Band II, erster Teil, 1104 pp. 

 Leipzig, 1891-93. (W. Engelmann). The appearance at this 

 time of the first two volumes of the new edition of Ostwald's 

 famous Lehrouch will no little enhance the rapidly growing 

 interest which has been aroused by the wonderful development of 

 all phases of the theory of chemical processes during the past 

 decade. Ostwald's style is historical and his treatment exhaus- 

 tive. The first volume takes up Stoechiometrie and includes the 

 modern Theory of Solutions. 



An unusual measure of interest is excited by the succeeding vol- 

 ume, on Chemical Energy, for the reason that here for the first time 

 in the history of chemical theory the General Doctrine of Energy is 

 exhaustively developed and applied. Thermochemistry, Electro- 



