NOTES AND ABSTRACTS IN CHEMISTRY AND PHARMACY. 
39 
three first are fixed on the fabrics by mordants, that is to say, metallic oxides ; 
garancine by alumina, or alumina and tin; cochineal by tin; and murexide by 
oxide of mercury or lead. The other colouring-matters may be fixed without 
mordants ; but aniline red prepared with arsenic is said to usually contain a 
certain quantity of arsenic. The following characters are those recommended 
by M. Tardieu for distinguishing these dyes:— 
Garancine red is not altered by solutions containing 3 to 4 per cent, of 
hydrochloric acid or of ammonia. The liquids are not sensibly coloured. The 
colour is the most resisting of organic reds. 
Cochineal red plunged into solution of ammonia changes to violet, and com¬ 
municates a very bright violet tint to the liquid. 
Murexide red bleaches rapidly in simple contact with a solution of citric 
acid. 
Carthamus red is completely decolorized by a short ebullition in a | per cent, 
solution of soap. 
Aniline red is decolorized very rapidly by contact with ammonia, but the 
colour is restored either by the addition of an acid or by the evaporation of the 
alkali. Marsh’s apparatus reveals traces of arsenic. 
Coralline red does not dissolve in cold water. It cedes a little of the colour 
to boiling water, but is decolorized much more rapidly and completely by boil¬ 
ing alcohol. Alkaline liquids do not turn the colour; acids precipitate the 
colouring-matter in yellowish flakes. 
To recognize a tissue dyed red by coralline, it is sufficient, according to M. 
Tardieu, to detach several fibres, cut them into small fragments, and submit 
them for several minutes to the action of a small quantity of boiling rectified 
spirit. The alcoholic liquid assumes a bright red, and the tissue, almost com¬ 
pletely decolorized, assumes an apricot-yellow tint. The addition of ammonia 
or caustic potash to the red alcoholic liquid brightens the colour, and distin¬ 
guishes definitely between coralline and aniline red. 
Detection of Prussic Acid in the Blood. 
In an article* on the toxicological investigation which took place on the 
murder of the Countess Chorinsky, M. Buchner gives some interesting remarks 
on the detection of prussic acid in the blood. In this case the blood was of 
clear cherry-red, and preserved this tint for several days. At the end of five 
days it was still perfectly liquid, and some weeks elapsed before it gelatinized. 
It resisted putrefaction for a long time when preserved in a stoppered bottle, 
but the red globules were destroyed in a few days. It presented no odour of 
prussic acid, but when diluted with water and distilled, the first portions of the 
distillate possessed a distinct smell of the poison, and gave positive results with 
the usual tests. By this means the acid was detected, even after the lapse of 
fifteen days. M. Buchner found Liebig’s test (sulphide of ammonium; to be 
the most delicate. 
Several years ago, Schonbein showed that the blood globules decompose, oxy¬ 
genated water liberating ordinary oxygen ; but the blood diluted with twice its 
volume of pure water, and containing a small quantity of prussic acid, loses 
almost entirely this catalytic action, while the mixture assumes a deep brown 
colour. This reaction affords the means of recognizing an infinitesimal quan¬ 
tity of prussic acid. Thus, if 50 grammes of defibrinated ox-blood be mixed 
with 450 grammes of water and 5 milligrammes of anhydrous prussic acid, the 
mixture becomes deep brown in presence of oxygenated water. In this case 
Buchner found Schonbein’s test to be a very valuable and delicate one. The 
blood, however, should not be very old, because then the blood has attained a 
deep colour, which the oxygenated water does not change. 
* ‘ Revue des Cours Scientifiques ’ and Journ. de Pharm. 
