172 On the Secretion of the Leaves and Stems of the Ice-plant. 
which the leaves are covered, with a needle, and collecting the 
fluid in a glass bottle. The fluid thus obtained was colourless 
and nearly” clear, without smell, and possessing no distinctly 
pronounced taste. Litmus-paper dipped in it was very slightly 
turned red, showing the presence of merely traces of a free acid 
or an acid salt. In order to free it entirely from any particles of 
epidermis which might accidentally have mingled with the liquid, 
I filtered it through white filtermg-paper. The fluid passing 
through the filter slowly was now perfectly clear. On heating 
to 212° F. white flakes were separated, which proved to be iden- 
tical with vegetable albumen. They were collected ina filter, and 
the filtrate evaporated to dryness on a water-bath. During the 
evaporation the liquid turned yellow, particularly when evapo- 
rated to a small bulk, and left a brownish-coloured, very hygro- 
scopic residue, which redissolved in a small quantity of distilled 
water, leaving but a trace of a humus-like, dark-coloured organic 
substance undissolved. 
The chemical nature of the fluid from which the albumen had 
been separated, was ascertained as far as possible by the follow- 
ing tests :— 
‘Ammonia produced no change. 
Carbonate of ammonia gave no precipitate. 
Carbonate of soda on boiling gave a white precipitate. 
Oxalate of ammonia produced no change. 
Phosphate of soda and ammonia, added to the concentrated 
liquid, gave a crystalline white precipitate of phosphate of mag- 
nesia aud ammonia. 
Chloride of platinum, added to the concentrated liquid after 
the removal of the magnesia, produced a crystalline yellow pre- 
cipitate. 
The presence of soda was indicated by the yellow colour given 
to the alcohol flame. 
Lime-water produced a white precipitate. 
Sulphate of lime hkewise produced a white precipitate. 
Chloride of barium gave a heavy white precipitate. 
Nitrate of silver gave a white flaky precipitate, soluble in am- 
monia, but insoluble in nitric acid. 
Acetate of lead produced a white precipitate. 
Basic acetate of lead gave a voluminous white precipitate. 
A portion of the water evaporated to dryness and heated to 
redness left a white ash which effervesced with acids, indicating 
the presence of echanptes, originated from organic acids present 
in the fluid. 
The nature of the organic acids, which in all likelihood ac- 
companied the oxalic acid, I could not determine from want of 
material. The presence of oxalic acid however is distinctly indi- 
