‘164 ODOROGRAPHIA. 
trated hydrochloric acid, after some time coniferin acquires an 
intense blue colour; in the sunlight this coloration is almost in- 
stantaneous. It is upon this reaction that the use of pne-wood as 
a test for carbolic acid is based. 
In order to determine the chemical constitution of coniferin, the 
investigators sought first to determine the nature of the products 
resulting from its decomposition with elimination of glucose. 
Dilute hydrochloric or sulphuric acid, aided by heat, splits it up 
into a resinous matter and glucose; but the properties of the 
resinous matter so obtained not appearing sufficiently definite, it 
was determined to effect the decomposition by fermentation by 
means of emulsin. For this purpose 50 grammes of pure coniferin 
were placed in 500 grammes of water, 0°2 to 0°3 gramme of dry 
emulsin added and the mixture kept at a temperature between 
25° and 26° C. The action commenced immediately, and in a few 
hours the presence of glucose in the liquor could be detected. The 
undissolved crystals of coniferin gradually disappeared and in their 
place were deposited at the bottom of the vessel white flocks, which 
were distinguishable from coniferin by their solubility in ether. 
After six or eight days the process of fermentation terminated, and 
by that time the bottom of the vessel was covered by a thick layer 
of this crystalline matter, the supernatant liquor being clear and 
slightly coloured. The liquor containing the precipitate was 
shaken with ether, which removed the flocks, and upon evaporation 
left a residue of well-formed white prismatic crystals. Sometimes, 
however, it left an oily residue, from which crystals were obtained 
upon cooling by a freezing-mixture. The crystals were pressed 
between filtering-paper and purified by recrystallization from ether. 
The aqueous solution, having had any remaining emulsin removed 
by coagulation by heat and filtering, was found to contain in 
solution only glucose and possible slight traces of undecomposed 
coniferin. The pure crystalline product, when recently prepared, is 
quite inodorous, but by exposure to the air graduatly acquires a 
feeble odour of vanilla. The pure product was reduced to fine 
powder and triturated with water, sulphuric acid and potassium 
dichromate in solution added, and the mixture distilled. At first 
a liquid smelling strongly of ethylic aldehyde was obtained; the 
next portions did not present this character, but were strongly acid 
and diffused a well-characterized odour of vanilla. From these 
portions of the distillate, ether removed a body which crystallized 
