6t Dr. Ure on Opium and its Tests. 



to me that the iron known to exist in the blood is probably in 

 the state of a sulpho-cyanate. A series of experiments was in 

 consequence instituted to determine the truth of this conjecture j 

 but the results have not hitherto enabled me to determine 

 whether sulpho-cyanic acid be one of the constituents either 

 of human blood, or that of the sheep, however liberally it is 

 supplied to the stomachs of both by the saliva. 



Blood freed in a great measure from its fibrin atid albumen, 

 was rendered slightly alkaline by carbonate of potash, and then 

 passed through a filter, with the view of separating the oxide 

 of iron from the sulpho-cyanate of potash, possibly formed. 

 The filtered liquor was next slightly supersaturated with phos- 

 phoric acid, and the mixture was distilled in glass at a gentle 

 heat. A colourless liquid came over, which did not change the 

 colour of litmus paper, but afforded, with a drop of permuriate 

 of iron, a tint faintly inclined to red, when compared with an 

 equal volume of water, to which a drop or two of the same 

 muriate had been added. 



It deserves to be noted, that the red colour produced by 

 the action of permuriate of iron on meconic acid, or a Aveak 

 solution of opium, has a brownish tint, distinguishable from 

 the deep orange-red of sulpho-cyanate of iron, diluted to the 

 same degree with water ; and by further dilution, the meconate 

 of iron merely pales its shade, but the sulpho-cyanate changes 

 it, somewhat abruptly, to a golden yellow. 



When opium is dissolved in porter (good London), the de- 

 tection of the drug becomes much more difficult than when it 

 is dissolved in strong beer ; for permuriate of iron produces 

 with porter (lightened with an equal volume of water) nearly 

 the same brownish colour, whether it be used as delivered by 

 the brewer, or mixed with laudanum to the extent of thirty 

 drops in two-ounce measures. A very copious grey-coloured 

 precipitate is thrown down from London brown stout by solu- 

 tion of acetate of lead — nearly as copious, in fact, as from por- 

 ter drugged, as above, with tincture of opium. And when 

 these two precipitates, washed on filters, are decomposed by 

 a little dilute sulphuric acid, they afford two liquids, which 

 strike nearly the same red-brown tints with permuriate of iron. 

 It is difficult to resist the evidence thus disclosed of the pre- 

 sence of opium in genuine London porter. Tincture of hop, 



