280 
PROCEEDINGS OE SECTION B. 
in hot water ; and if too much water has not been added, it again 
becomes turbid as it cools, and if then placed under the microscope it is 
readily seen how the globular cauliflower-headed masses form, as the 
turbidity is seen to be caused by little globules. These appear to 
congregate together in groups, and when further evaporated in the 
air they form together in little lumps of these globules, which do not 
break. There is no sign of crystallisation, nor were any signs of crystal- 
lisation seen by any method, although most carefully sought for with 
a i-inch objective. Several methods were tried, with all solvents 
. — air dried, dried in vacuo, dried on the bath, all without result. 
“When the alcoholic extract from the dried oxide of lead is evaporated 
to a small bulk and allowed to stand, water is absorbed, and these 
globular cauliflower masses form in a day or two. When spread on a 
piece of glass it is transparent, and remains so after some days, the 
only perceptible difference being the formation of the globular masses. 
Although fairly pure, yet it was not sufficiently so for research 
work, and required*to be further purified. One of two methods may 
be used. First, dissolve the thus purified substance in a small quantity 
of alcohol and precipitate with ether; allow to stand twenty-four 
hours, when the glucoside will have been precipitated as a thick mass 
at the bottom ; pour off the ether and alcohol ; wash with ether ; dry in 
the air ; dissolve in water; place in separator, and extract with arnylic 
alcohol with continued portions of fresh extractive, well agitating the 
solutions; the arnylic alcohol thus obtained is evaporated to dryness at 
a low heat over the water bath, when an amorphous substance is left 
which is but slightly deliquescent, slightly yellowish-brown, very 
bitter and of nasty taste ; does not reduce an alkaline solution of copper 
in the cold, but slightly reduces it on raising to the boiling point, and 
instantly if inverted. ’ This substance gives splendidly clear reactions, 
and may be considered as fairly pure. By this mode of proceeding 
there can be little besides this active principle present, all else 
having been removed by the previous processes. Secondly, if the 
roughly purified substance as obtained from the oxide of lead is 
dissolved in warm water, filtered, and, when cold, tannic acid added 
in excess, a precipitate forms, which after standing some time is 
removed, washed in water once or twice, and, while still moist, oxide of 
lead is added and then evaporated to dryness, the dried residue again 
being boiled out with alcohol. The second process might be con- 
sidered the more accurate, as we might expect to obtain a purer 
product by precipitating it in this way ; but there are several reasons 
whv the first process is the better. First, the whole is not precipitated 
with tannic acid; secondly, a considerable portion is removed on 
washing ; thirdly, as a final result the glucoside does not appear to be 
able to°stand being boiled even with alcohol without partly decom- 
posing; and, fourthly, the product is small in quantity, so that for 
future experiments we shall obtain the glucoside by the method of 
extraction from the aqueous solution of the roughly purified material 
precipitated by ether from alcohol. 
When boiled in dilute acid, the liquid, if fairly dilute, remains 
c ]ear while boiling, but becomes turbid on cooling ; the decomposition 
product therefore is not soluble iu cold acid aqueous solutions, and 
may perhaps, be removed in a pure state by extraction from the 
aqueous solution, so that its chemical composition and reactions may 
