484 Dr. Stenhouse on Aloine, the Cathartic Principle 



cold aqueous solution of aloine, a bright yellow precipitate is 

 immediately produced, the amount of which increases on 

 standing, while at the same time the supernatant liquid becomes 

 very acid from containing free hydrobromic acid. The pre- 

 cipitate, after it has been washed with cold water to remove 

 adhering acid, is dissolved in hot spirits of wine ; and on the 

 cooling of the solution it is deposited in bright yellow needles 

 radiating from centres, which attach themselves to the bottom 

 and sides of the containing vessel. 



The crystals of brom-aloine are considerably broader than 

 those of aloine, and have a richer yellow colour and a higher 

 lustre. Brom-aloine is quite neutral to test-paper, is not so 

 soluble in either cold water or cold spirits of wine as aloine, 

 but dissolves very readily in hot spirits of wine. 



I. 0'421 grm. substance dried in vacuo gave 0*547 car- 

 bonic acid and 0*1 OS water. 



0-856 grm. gave 0*848 bromide of silver = 42*16 Br. 



II. 0*300 grm. substance gave 0*391 carbonic acid and 

 0=078 water. 



0*661 grm. substance gave 0*649 bromide of silver = 0*2762 

 Br = 41*78 per cent. 



34 C . . 



15 H . . 



140 . . 



3 Br . . 



7136*39 100*00 100*00 100*00 



The brom-aloine employed in these analyses was prepared 

 at two different times. It is plain therefore from these results, 

 that this bromine compound is aloine, C 34 H 18 O 14 , in which 

 3 equivs. of hydrogen are replaced by 3 equivs. of bromine. 

 The formula of brom-aloine therefore is C 34 H 15 O 14 Br 3 . 



When a stream of chlorine gas was sent for a considerable 

 time through a cold aqueous solution of aloine, a deep yellow 

 precipitate was produced. It contained a great deal of com- 

 bined chlorine; but as it could not be made to crystallize, it 

 was not subjected to analysis. In the present instance, and 

 in those of several other feeble organic principles, such as 

 orcine, chlorine appears to act somewhat too strongly, so that 

 the constitution of the substance is destroyed, and merely un- 

 crystallizable resins are produced. Bromine, on the other 

 hand, is much more gentle in its operations, and usually simply 

 replaces a moderate amount of the hydrogen in the substance, 

 so that, as in the case of orcine and aloine, crystalline com- 

 pounds are produced. 



Calculated numbers. 



I. 



n. 



2550*00 



35*73 



35'43 



35*53 



187*50 



2*62 



2*71 



2*86 



1400-00 



19*63 



19*70 



19*83 



2998*89 



42*02 



42*16 



41*78 



