554 Transactions.— Chemistry. 
liquid, into the solution to be tested. Usually the precipitate thus made 
will at first dissolve. In such cases more of the test liquid is added until 
the precipitate or turbidity ensuing is permanent. 
The instances to which this modifiation of the mercuro-iodide test has 
been found to be applicable are aconite, atrophia, colchicum, morphia, and 
veratria, among the alkaloids; caseine and gelatine among the albuminoids. 
It is also applicable to solutions of digitalin and urea. Those to which 
I have ascertained it to be unapplicable are codea, narcotina, nicotina, 
quinine, strychnia and albumen, this last group forming such insoluble 
compounds with iodide of mercury, prepared as first indicated, that mer- 
eurie chloride is not needed with them; strychnia, for instance, giving a 
distinct cloudiness with it when present in a solution as but qso roo part of 
it, quinine affecting this when only in a 5,4154; part, narcotina as I004-997 
part ; and albumen, hydrous as it exists in eggs, reacting in a similar way 
when present in only the 551,55 part. 
I append a few approximate determinations as to the degree of delicacy 
this test (the mercuric iodide and chloride conjoined) admits of in the case 
of a few of the substances cited in the first group. 
Atrophine 55.455 a distinct cloudiness. 
Morphia 4544555 
Verairià asorot 55 
For comparison of this test with the best of those hitherto used I may 
state that morphia and gelatine do not give a decided precipitate with 
these, except it is present in not less than the 5.000 Part of the liquid to 
which the test is applied. 
I should state that the liquid suspected to contain an alkaloid should be 
made neutral, or eare should be taken that no free mineral acid is present ; 
this is readily accomplished by adding thereto sufficient acetate of soda. 
The exact composition of the various preeipitates formed in this way has 
not yet been ascertained ; they of course mainly, if not altogether, consist of 
the alkaloid or albuminoid used together with iodine and mereury, but 
whether in any ease chlorine forms a part, I do not yet know, but I believe 
it does not. Various useful and interesting faets in connection with this 
subject have been ascertained in the course of this investigation, and which 
I will shortly state. 
In the first place, I find that the compounds of the alkaloids generally 
with iodine and mereury are readily soluble in ether, and to such an extent 
that they can be removed from their aqueous solution acidified with acetic 
acid, by this liquid, as in ** Stas's process," and the etherial solution leaves 
the triple eompound in a granular form; this, dissolved in aleohol, and 
allowed to stand a few-hours with thin strips of eopper, or agitated a short 
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