508 Dr. Schunck on Ruhian and its Products of Decomposition, 

 4 atoms of carbonic acid, 2 atoms of water and 1 of lime, for 

 CM H3« N2 0^ + 3CaO + 4C02 + 2H0 + CaO 

 =C^H34N2 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 eiythrozym 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 liltcr, washed with w^ater 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 pro- 

 cess of purification, have undergone decomposition. 



0*5695 grm., burnt with oxide of copper and chlorate of 

 potash, gave 0*9585 carbonic 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 acid, 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 corre- 

 spond to the following composition : — 



650 10000 



It appeal's, 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 



