374 
ON THE MELTING AND SUBLIMING TEMPERATURES 
2. Sublimation without Change of Form or Colour, followed by Melting, with or 
without Change of Colour and with further Sublimation. —This class includes the 
three poisons— oxalic acid, morphine, and strychnine. The first (oxalic acid) sub¬ 
limes, then melts, and is dissipated without residue. The second and third 
(morphine and strychnine) first yield sublimates, then melt and darken, con¬ 
tinue to sublime, but leave a distinct layer of carbon. These changes take place 
at the temperatures indicated below :— 
Oxalic acid sublimes at or about 180°, melts at or about 280° 
Morphine ,, ,, 330° ,, 340° 
Strychnine ,, ,, 345° ,, 430° 
3. Melting, Change of Colour, and Sublimation. —This class comprises all the 
poisonous alkaloids and glucosides, except the members of class 2,—morphine 
and strychnine. Their melting and subliming temperatures are giveu below, ar¬ 
ranged in the order of their melting temperature, beginning with the lowest:— 
Aconitine melts at or about 140°, sublimes at or about 400° 
Atropine 
11 
11 
150° 
11 
280° 
Delphinia 
11 
11 
150° 
11 
»» 
300° 
Veratrine 
11 
11 
200° 
11 
360° 
Brucine 
11 
11 
240° 
11 
)> 
400° 
Digitaline 
11 
11 
310° 
11 
310° 
Picrotoxia 
11 
11 
320° 
11 
jj 
320° 
Solanine 
11 
11 
420° 
11 
420° 
I add a statement of the 
melting and subliming temperatures of 1 
bers of the opium-series :— 
Meconine melts at or about 120°, sublimes at or about 180° 
Narceine 
Paramorphia ,, 
Papaverine ,, 
Codeine ,, 
Narcotine „ 
Cryptopia 
>» 
»» 
170° 
210 ° 
210 ° 
220 ° 
240° 
350° 
)•> 
V 
1» 
JJ 
J1 
»» 
*1 
430° 
320° 
310° 
220 ° 
310° 
350° 
All these substances, it need not be stated, yield, like morphine and strych¬ 
nine, a more or less abundant carbonaceous residue, by which the alkaloids and 
glucosides are distinguished from most other bodies. To these distinctive cha¬ 
racters that of giving out a marked odour, in some cases agreeable, in others 
offensive, ought to be added. As the result of repeated careful experiments, 
both with platinum-foil and the porcelain slab, I give the following:—Strych¬ 
nine, pleasant but not easy to describe; morphine and atropine, as of singeing ; 
brucia, as of burnt horn ; aconitine, not disagreeable, but ill-defined ; veratrine, 
mousy and irritating to the nostrils ; digitaline, as of the drug ; solanine, as of 
roast apple. 
On comparing class 2 with class 3, it will be obvious that, with common care 
in applying heat, it would not be possible to confound the two important alka¬ 
loids, morphine and strychnine, with any other known poisons. A white 
powder or crushed crystal, which first sublimed at 330°, or from that to 345°, 
melted at some higher temperature, and continued to yield sublimates till it left 
a final carbonaceous deposit, must be either morphine or strychnine. If both 
changes happened at the lower temperatures indicated in the table, it would be 
morphine ; if at the higher, strychnine. The peculiar white disks developed in 
the sublimate are common to the two alkaloids, and the forms of the sublimates 
might also not prove characteristic. Hence it might be necessary to resort to 
the colour test or the carbazotic-acid test, to render the diagnosis certain. A 
glance at the tables will show that many of the alkaloids or glucosides melt and 
sublime also at temperatures so low as not to admit of being confounded with 
either of these important poisons. 
