Letter Captain Parry to Professor Jameson. 589 
kntic so loaded as our necessities require, in order to enable us 
to proceed with perfect confidence in our resources. These we 
can now, without much pinching or inconvenience, extend to a 
period of three years and a half from this time. I trust that, 
with the continued blessing of God upon our endeavours, we 
may do something worthy of so liberal and splendid an equip- 
ment. 
I am very much pleased with your friend and pupil Dr Neill, 
with whom I am making every arrangement in my power to 
promote the interests of natural history in each of its depart- 
ments ; for, though I can lay no claim to acquirements in 
this way myself, I am most anxious to leave nothing undone 
which may, in any way, be beneficial or interesting. We are 
making every preparation for the collections of specimens, which 
may at once save time and trouble in making them, and pre- 
serve them in the best order for examination and description 
hereafter. I am, &c. F. Parry. 
Art. XXV . — On the Detection of Minute Quantities of Ar- 
senic in mixed Fluids *. By Robert Christison, M. D. 
F. R. S. Professor of Medical Jurisprudence in the University 
of Edinburgh. 
ft* 
Jl HE object of this paper is to estimate the value of the liquid 
tests for arsenic, when dissolved in mixed vegetable and animal 
fluids, and of the various processes which have been proposed 
for correcting the changes thus produced in the action of the 
tests ; and, finally, to determine, what mode of analysis is at the 
same time the simplest, and may be applied under all circum- 
stances. The author has extended the researches of Orfila, and 
those on the modifications caused in the action of the tests, by 
the co-existence of animal and vegetable fluids ; and shews, by 
the instances of broth, tea, coffee, porter, Port-wine and milk, 
that, when the fluid is complicated, or deeply coloured, and the 
arsenical solution of such moderate strength as may be usually 
looked for in medico-legal investigations, the four best liquid 
tests, namely, lime-water, the ammoniacal sulphate of copper, 
* The above is a condensed view of Dr Chvistison’s interesting Memoir in the 
Edinburgh Medical Journal for July 1824. 
