172 POISONS : TIIEIR EFFECTS AND DETECTION. [§ 208. 
It will give a white precipitate of calomel when treated with mercuric 
chloride solution— 
(HCOO) 2 Mg-f 4HgCl 2 =2Hg 2 Cl 2 + MgCl 2 + 2HC1+ 2C0 2 . 
Chloral (or chloroform), when boiled with resorcinol and the liquid 
made strongly alkaline with NaHO, gives a red colour, which disappears 
on acidifying and is restored by alkalies. If, on the other hand, there 
is an excess of resorcinol and only a very small quantity of NaHO used, 
the product shows a yellowish-green fluorescence ; ^ of a milligramme 
of chloral hydrate gives this reaction distinctly when boiled with 50 
mgrms. of resorcinol and 5 drops of a normal solution of sodium hydrate. 1 
Dr Frank Ogston 2 has recommended sulphide of ammonium to be 
added to any liquid as a test for chloral. The contents of the stomach 
are filtered or submitted to dialysis, and the test applied direct. If 
chloral is present, there is first an orange-yellow colour ; on standing, 
the fluid becomes more and more brown, then troubled, an amorphous 
precipitate falls to the bottom, and a peculiar odour is developed. 
With 10 mgrms. of chloral in 1 c.c. of water, there is an evident pre¬ 
cipitate, and the odour can readily be perceived ; with 1 mgrm. dissolved 
in 1 c.c. of water, there is an orange-yellow colour, and also the odour, 
but no precipitate ; with *1 mgrm. in 1 c.c. of water, there is a weak, 
pale, straw-yellow colour, which can scarcely be called characteristic. 
The only substance giving in neutral solutions the same reactions is 
antimony ; but, on the addition of a few drops of acid, the antimony 
falls as an orange-yellow precipitate, while, if chloral alone is present, 
there is a light white precipitate of sulphur. 
§ 208. Veronal, C 8 H 12 N 2 0 3 = (C 2 H 5 ) 2 .C.(C0NH) 2 C0 (syn. barbitone, 
diethyl-barbituric acid, malonurea), crystallised from hot benzene and 
petroleum ether, forms rhombic crystals, soluble in 12 parts of boiling 
water, 168 parts of cold, and easily soluble in alcohol, ether, and alkaline 
solutions; melting-point, 191° C. ; easily sublimable without residue. 
The aqueous solution reacts acid and has a bitter taste. Mercurous 
nitrate gives a white precipitate; Millon’s reagent, a gelatinous yellow 
precipitate, soluble in excess. Veronal can be extracted from animal 
tissues by alcohol; the final alcohol extract is dissolved in weak solution 
of soda or potash acidified by hydrochloric acid, and extracted by ether. 
The ethereal extract is dried, the dry residue sublimed, and tests made 
upon the sublimate. 
Jorissen's reaction. —Equal parts of caustic alkali and veronal are 
heated for two minutes to fusion; the cooled mass is dissolved in a very 
small quantity of water. In one portion the formed prussic acid is identi¬ 
fied ; another portion is acidified with sulphuric acid and shaken out with 
1 C. Schwai'z, Pharm. Zeit., xxxiii. 419. 
2 Vierteljahrsschr. f. gerichtl. Medicin, 1879, Bd. xxx. Hffc. 1 , S. 268. 
