PRESERVATION OF SYRUP OF IODIDE OF IRON. 
421 
The fluorescence of a slightly alkaline solution of the sesculet.in obtained as above 
is the most beautiful instance of that phenomenon that has ever come under my 
notice. It is finely seen when the solution is illuminated by the light of 
sulphur burning in oxygen. 
The cause of the loss of bitterness which the liymenodictyon bark suffers by 
keeping is more readily explained. iEsculin, by contact with changing organic 
substances, becomes slowly converted into aesculetin, and glucose by the same 
decomposition that can be more immediately produced by boiling with acids. 
When a solution of sesculinis mixed with emulsion of sweet almonds, the change 
takes place in about two days. The soluble bitter substance of the fresh bark gra¬ 
dually changes into the sparingly soluble aesculetin, which has comparatively little 
taste, the bark becoming less bitter from day to day. That this is really the 
case can be experimentally shown by boiling a few fragments of stale bark in a 
test-tube with some water ; on cooling, an abundance of glittering crystals will 
be deposited, which can readily be recognized by their form and their behaviour 
towards polarized light. They form beautiful microscopic objects. Perfectly 
fresh bark yields no sesculetin when thus treated. 
The bark of Hymenodictyon excelsum differs entirely in its chemical characters 
and products from cinchona bark. Containing no trace of quinine, the expec¬ 
tations once entertained of its medicinal value appear to have but little support 
in fact. 
Professor Bentley said the paper was extremely interesting in a chemical 
point of view. The bark referred to was another instance of one of those 
facts which chemists had recently brought to light, that similar substances 
were to be found in plants of totally different Natural Orders, and having 
not the slightest botanical relation to each other. The writer had men¬ 
tioned the case of tea and coffee, but he might have added that the same sub¬ 
stance which was the constituent in tea and coffee was also found in two other 
Natural Orders. Another remarkable instance of the same fact was the case of 
berberine, a substance remarkable for the number of plants in different Orders 
in which it was found. Therefore, the discovery of another substance in the 
Order Rubiacese, similar to that found iu the horse-chestnut, which belonged 
to the Sapindaceae, was not without many parallels, but at the same time such 
discoveries were extremely interesting to the chemist and pharmaceutist. 
PRESERVATION OE SYRUP OF IODIDE OF IRON. 
BY THOMAS B. GROVES, F.C.S. 
The appearance of Mr. Tilden’s paper on the above subject has suggested the 
publication of the following note of experiments in the same direction made in 
May, 1865. 
Having heard expressed the opinion that syrup of iodide of iron when made 
from iron filings kept better than a corresponding syrup made from pure iron 
in the form of wire, it occurred to me that such (supposing the statement to be 
true) could only arise from the presence, in the syrup, of substances owing their 
existence to the impurities usually found in the iron from which filings are 
commonly obtained. 
The most prominent of these impurities and those only likely to be concerned 
in this matter are phosphorus and sulphur, which when treated in the presence 
of water, with excess of iodine, form respectively phosphoric and sulphuric acids, 
according to the following equation :— 
p + I 5 + 8H0 = P0 5 ,3H0,5HI. 
