160 ODOROGRAPHIA. 
inner side, the operation is stopped. When cooled, the contents 
of the flask are removed into a well-stoppered bottle, and shaken 
three or four times with not too small quantities of ether (from 
400 to 600 c.c.) ; the ether takes up all the vanillin present. The 
ethereal extracts are separated from the aqueous solution and dis- 
tilled together from a large flask, down to 15 or 20 c.c. The last 
part of the operation is conducted very cautiously, the temperature 
of the contents of the flask being raised with a little steam to a 
point not beyond 50° or 60° C. The residue, which is of a faint 
yellow colour, is placed in a weighed watch-glass, washed carefully 
with pure ether, and the ether allowed to completely evaporate at 
the ordinary temperature. If the operation has been properly 
conducted, and especially if a too strong heating of the concen- 
trated vanillin solution has been avoided, pure crystals of vanillin 
are formed, melting at 81°C. These are dried over sulphuric acid 
until they no longer lose weight. The solution of acid sulphite of 
sodium can be recovered. 
«The above process may also be used for the detection of adulte- 
ration of vanilla, by perfuming it with such substances as benzoin 
&e. These remain behind in the ethereal extract after the removal 
of the vanillin, and may then be easily recognized.” 
Vanillin—The results of the analyses made by Tiemann and 
Haarman * show the proportion of vanillin in various pods to be as 
follows :— 
MPEXICAN, 
1. First quality. Harvest 1873.......... 1:69 per cent. 
2:3) 1% + of) STA. a scene 186 * 
3. Medium ,, 5 ee 1:32 9 
Bovurpon. 
1. Wrest: quality. “Harvest 1874%.7.. >. ee 2°48 per cent. 
Zee 3s, 7 if jy Nag tite 1‘91 3 
3. ” ” ” 59. sega feveheyaie aue 9:90 ” 
Aas 3 pn A8TOn scene 1:97 ip 
0. 5, ” ” rR ein oe 2°45 = 
6. Medium _,, a sa tape rebel Teas hehe ke LA9 3 
7. Inferior _,, 95° LSTA oooerne 1:55 35 
8. 4 ¥ 99 «UBB ee den eaves O75 as 
JAVA. 
1, First quality. Harvest 1873.......... 2°75 per cent. 
2, Medium ,, oy. ASHE: Acumen 1°56 a 
* Ber. Deutsch. chem. Ges. viii. p. 1118, & ix. p. 1287. 
