102 MR. SCHUNCK ON RUBIAN AND ITS PRODUCTS OF DECOMPOSITION. 
If this composition be compared with that of the substance in its undecoraposed 
state, the exact nature of the change which it undergoes during the process of 
fermentation will be apparent. It appears that the change consisted in this case in 
the loss of 4 atoms of carbonic acid, 2 atoms of water and 1 of lime, tor 
C 52 H 32 N 2 O30+3CaO+4CO24-2HO+CaO=C56 H 34 N 2 0,o+4CaO. 
It appears also that no loss had been sustained in the nitrogen. The atom of lime 
lost was probably abstracted by the carbonic acid disengaged at the same time. 
In order to obtain, if possible, the organic substance, which is contained in the 
erythrozym in combination with lime, and to which the name of erythrozym ought 
perhaps to be restricted, in a free state, I prepared an extract of madder with tepid 
water, and added to it tartaric acid. A brown precipitate was produced, which was 
collected on a paper filter, washed with water in order to remove the excess of acid, 
then treated with boiling alcohol, until everything soluble in that menstruum was 
removed, and lastly, washed with cold water, in order to separate any pectic acid 
which might be present ; after which it was dried. Its analysis showed, however, 
that the acid had removed only half of the lime, and that the substance itself must, 
during the process of purification, have undergone decomposition. 
0‘5695 grm., burnt with oxide of copper and chlorate of potash, gave 0 9585 cai- 
bonic acid and 0-2600 water. 
0-5940 grm. gave on being incinerated 0-0900 carbonate of lime, containing 0 0505 
lime = 8-50 per cent. 
0-2835 grm. gave on being incinerated, and then treated with sulphuric aci , 
0-0560 sulphate of lime, containing 0-02310 lime =8-14 per cent. The average 
per-centage of lime was therefore 8-32. 
The nitrogen was not determined ; but presuming no loss to have taken place in 
that constituent, then these numbers correspond to the following composition : 
Eos. 
Calculated. 
Found. 
Carbon . . . 
. 52 
312 
48-00 
47-68 
Hydrogen . . 
, . 30 
30 
4-61 
5-07 
Nitrogen 
. . 2 
28 
4-30 
Oxygen . . 
. . 28 
224 
34-48 
Lime . . . 
. . 2 
56 
8-61 
8-32 
650 
100-00 
It appears, therefore, that the decomposition of the substance had advanced in 
this case still further even than in the last, as it contained 2 equivs. of water less. 
The last specimen I examined was one which was prepared in the usual manner 
by precipitation with alcohol, then mixed with water and allowed to decompose 
until bubbles of gas began to be disengaged, and the smell peculiar to this substance 
when in a state of putrefaction began to be emitted, then treated with boiling 
alcohol until nothing more was dissolved, and dried. 
