— 42 



According to him, most of these reactions are useless; only that of 

 Dodge and Olcott, and Turner's test are said to yield unimpeachable 

 results. According to Dodge and Olcott, 4 to 6 drops of con- 

 centrated nitric acid are added to a solution of 4 drops of copaiba 

 balsam in 15 cc. of glacial acetic acid. Pure copaiba balsam remains 

 unchanged; when gurjun balsam is present the glacial acetic acid solution 

 becomes purple. In Turner's reaction, 3 to 4 drops of copaiba 

 balsam are dissolved in 3 cc. of glacial acetic acid, a drop of freshly 

 prepared 10 per cent, sodium nitrite solution is added to the solution 

 and the latter is then very carefully poured upon 2 cc. of concentrated 

 sulphuric acid. In the case of pure copaiba balsam the glacial acetic 

 acid layer remains colourless, while if gurjun balsam is present, the 

 solution gradually turns violet. 



We made a control test of the two reactions referred to, and were 

 able, on the whole, to corroborate the statements of Utz. But it 

 must be noted that in Dodge's and Olcott's test the colour occasion- 

 ally disappears very rapidly, while in the case of Turner's test the 

 minutest care was necessary to carry out the overlaying of the sulphuric 

 acid; otherwise the glacial acetic acid layer, instead of remaining 

 colourless, turned brown very easily. 



In connection with this matter we may point out that of the 

 various balsams mentioned in our Report April 1 905 1 ) the Para balsam, 

 strange to say, gives the gurjun balsam reactions referred to above, 

 so that it is scarcely doubtful that this balsam also was adulterated 

 with gurjun balsam. As already mentioned by us at the time, these 

 balsams had come to us at first hand, and therefore we had no 

 reason at the time of doubting their genuineness, as in most cases 

 adulterations are only resorted to by middlemen. In any case, the 

 last thing that could be surmised was that in South America, the 

 country of origin, gurjun balsam, which is an East Indian product, 

 would have been added, for which reason even the high optical rot- 

 ation of the balsam did not make us suspicious with regard to its 

 quality. We therefore desire to take this opportunity of correcting our 

 views as to the Para balsam. We may again quote the constants which 

 it was found to possess: d^o 0,9692, «d — 4i°2o' acid no. 60,75, 

 sap. no. (cold) 64,72. To water vapour it yielded 62,5 °/ of a yellow 

 oil: di 5 o 0,9180, «d — 78°48', acid no. 3,14, ester no. o. 



Coriander Oil. Plentiful supplies of this oil were available at 

 unchanged prices; but, should the demand become brisker, it is probable 

 that the quotation will have to be raised, as in that case the supplies 

 will scarcely last until the next crop is available. 





x ) Report April 1905, 24. 



