EDINBURGH MEETING. 
337 
ticular precaution, and, as they could see, no discoloration had taken place. In¬ 
deed, he never expected it would. At the same time, cases had come under his 
notice where the syrup had undergone a change of colour, and that very soon ; 
but these were cases in which he had never been able to satisfy himself that 
proper care had been exercised, and he believed—though he had no positive proof 
of the fact—that when the syrup speedily underwent a change of colour, it arose 
from one of the following causes,—either that inferior sugar was used or an in¬ 
sufficient quantity, or that the syrup, after it was made, had been exposed to an 
impure atmosphere. Generally speaking, he believed the cause of failure lay in 
the sugar, for a great deal of refined sugar of commerce was far from being 
pure. He believed that if syrup were carefully made with the purest refined 
sugar, it would keep perfectly well if it met with no atmospheric contamination 
afterwards. Any one who had any experience in a laboratory was aware that 
the atmosphere was very often impure; sometimes there were ammoniacal 
vapours floating about, and sometimes the fumes of nitric acid, and if these 
had access to so delicate a substance as syrup of iodide of iron, they could easily 
understand that decomposition would take place. He was desirous of throwing 
out these suggestions for verification, for, as he had said, he was not able at 
present to demonstrate the fact that the discoloration took place in this way, 
but if it were so, it would account for the discrepancies in the experience of 
different operators. 
Mr. Carteighe asked if the specimens brought from the museum had been 
kept in the light or in the dark. 
Dr. Redwood said they were not exposed to direct sunlight, nor were they 
kept in the dark ; but he had had some specimens kept upstairs in a more se¬ 
cluded situation with the same result, and he should be surprised at finding any 
discoloration. They were always kept in clear glass bottles, which might 
have a different effect to that produced by opaque stone jars. 
Mr. Carteighe would like to know what Dr. Redwood considered pure 
sugar. He presumed he meant bond fide cane sugar, not beet sugar. 
Dr. Redwood was not aware that there was any chemical difference between 
caue and beetroot sugar. The impurities he referred to were those which arose 
from the presence of the remains of the materials used in refining the sugar. 
Sometimes there were traces of lime, or salts of lime, or albuminous matter : there 
were great differences in different varieties of sugar in this respect. He should 
select a sugar that would form a clear and transparent solution, and if it would 
not, it should be clarified before using for such a purpose. The French were 
very particular, in making syrups, to well clarify their syrup before using it, al¬ 
though they used refined sugar, not taking it for granted that the sugar was 
entirely free from foreign matter, as such was rarely the case. 
EDINBURGH MEETING. 
The first meeting of Session 1869-70, was held in St. George’s Hall, 119a, George 
Street; Mr. Aitken, President, in the chair. There was a full attendance. 
The Secretary intimated the following presentations to the Library:—Baildon’s 
‘Nature-Printed Ferns,’ and ‘HortusMedicus,’ by George Graves and Dr. J. D. Morries, 
with coloured plates: Mr. H. C. Baildon. ‘ Manual of Materia Medica and Therapeutics,’ 
by Dr. Milne: from the Publishers, Messrs. Livingstone, Edinburgh. ‘Index to Twelve 
Volumes of the Pharmaceutical Journal:’ from the Society in London. Proceedings of 
the American Pharmaceutical Association: from the Association. September and 
October Number of the ‘Pharmacist:’ from America. 
The President gave the following Address :— 
