^\lrl\%I^s-''^'}  Chemical  Examination  of  Cincho-^inine. ,  159 
der  Chemie,"  vol.  7,  part  2,  p.  1720),  is  distinctive  of  quinidia  from 
quinia  in  concentrated  solutions. 
2.  Chlorine  water,  followed  by  ferrocyanide  of  potassium,  and  then 
ammonia,  produced  a  dirty  brownish-red  precipitate,  which,  according; 
to  Schwarzer  {vide  "  Gmelin's  Handbuch  der  Chemie,"  vol  7,  part  2,  p, 
iJ2o),  is  distinctive  of  quinidia  from  quinia  in  concentrated  solutions. 
3.  The  addition  of  tincture  of  iodine  to  their  solution  in  dilute  alco- 
hol containing  excess  of  sulphuric  acid,  produced  an  orange-brown 
precipitate,  which,  when  redissolved  by  gentle  heat,  and  allowed  to 
deposit  by  gradual  cooling,  was  found  to  consist  mainly  of  a  volumi- 
nous orange-brown  precipitate,  interspersed  with  a  few  black  crystals 
of  herapathit. 
Result  E. — By  our  experiments  we  have  proved  that  there  is  no  very 
appreciable  difference  in  the  quantities  of  in  ether ^  soluble  alkaloids  and  of  quinia 
contained  in  the  various  samples  of  cinch o-quinine  examined. 
CONCLUSION. 
The  results  of  the  three  series  of  experiments — qualitative  and 
quantitative — may  be  summed  up  in  the  following: 
1.  Cincho-quinine  is  composed  mainly  of  cinchonia,  a  considerable 
portion  of  which  is  in  combination  with  sulphuric  acid,  and  is,  there- 
fore, sulphate  of  cinchonia. 
2.  It  contains  less  than  i  (one)  per  cent,  of  the  alkaloid  quinia, 
which  exists  either  in  alkaloid  or  as  sulphate. 
3.  It  contains  less  than  5  (five)  per  cent,  of  the  alkaloid  quinidia,. 
which  exists  either  as  alkaloid,  or  as  sulphate. 
4.  If  it  contains  any  cinchonidia  at  all,  this  can  be  present  only  in 
very  small  quantities  ;  since  the  residue,  remaining  after  exhausting 
precipitated  cincho-quinine  with  ether,  did  not  contain  it,  and  it  could 
therefore  have  been  contained  only  in  the  ethereal  extraction,  in  which 
we  did  not  search  for  it. 
5.  It  contains  traces  of  sulphate  of  ammonium,  and  is  therefore  pre- 
cipitated from  combination  with  sulphuric  acid,  by  ammonia. 
6.  It  is  not  an  alkaloidal  representative  of  cinchona  bark. 
Finally,  we  propose,  in  the  following,  to  correct  some  statements 
made  in  the  circular,  described  in  the  appendix  to  this  paper,  and  to 
correct  some  impressions  that  the  authors  of  these  circulars  evidently 
intend  to  convey  : 
I.  In  their  circular  (described  as  No.  i)  the  following  statement  is 
made  : 
