Am"  NOTr'i884arm* }         Homoquinine  of  Cuprea  Bark,  577 
crystals  from  the  ether  solution,  as  would  have  been  the  case  with  even 
a  very  dilute  solution  of  ammonia  had  been  used  in  place  of  caustic 
soda.  Upon  separating  the  ethereal  liquor,  neutralizing  the  alkaloid 
contained  in  it  with  sulphuric  acid  and  evaporating,  a  crystalline  sul- 
phate was  obtained,  which  when  tested  in  the  usual  way  with  ether 
and  ammonia  behaved  exactly  like  quinine  sulphate,  no  vestige  of 
homoquinine  crystals  being  formed  even  after  the  lapse  of  several  days. 
This  result  appeared  to  be  exactly  the  same  as  that  obtained  by  Dr. 
Hesse,  except  in  one  particular,  viz.,  that  it  was  not  obtained  by  degrees, 
as  Dr.  Hesse's  description  would  suggest,  but  at  once  and  without  any 
need  for  the  "repeated  precipitations7'  mentioned  by  Dr.  Hesse.  This 
discrepancy  led  us  to  repeat  the  experiment  several  times,  invariably, 
however,  with  the  same  result,  which  seemed  to  be  conclusively  opposed 
to  the  doubt  we  entertained  as  to  the  conversion  of  homoquinine  into 
quinine.  But  on  further  consideration  of  the  matter  and  havings  as  is 
our  general  practice,  regard  to  the  quantitative  relations  of  the  experi- 
ment, we  observed  that  the  quantity  of  alkaloid  permanently  soluble 
in  ether  thus  obtained  was  never  more  than  about  one-half  that  of  the 
homoquinine  operated  upon.  The  solubility  of  quinine  in  solution  of 
caustic  soda  is  too  slight  to  account  for  this  deficiency.  Still  we  found 
that  on  adding  to  the  caustic  soda  liquor  with  which  the  homoquinine 
had  been  treated  in  these  experiments,  sufficient  sulphuric  acid  to  make 
it  faintly  acid,  there  was  a  copious  precipitation  of  a  crystalline  sul- 
phate, the  quantity  of  which  accounted  for  the  deficiency  above  men- 
tioned. The  alkaloid  contained  in  this  salt  was  not  quinine;  it  crys- 
tallized readily  from  solution  in  ether  in  rhombic  plates,  larger  and 
more  massive  than  the  ordinary  crystals  of  homoquinine  and  otherwise 
presenting  a  character  distinctly  different  from  them.  The  alkaloid 
thus  obtained  was  again  treated  with  caustic  soda  solution  and  ether, 
but  it  gave  no  evidence  of  being  thus  convertible  into  quinine;  the 
whole  of  it  remained  dissolved  in  the  soda  solution  and  was  easily 
obtained  again  in  the  crystalline  state  by  subsequent  treatment  in  the 
ordinary  way  with  ether  and  ammonia.  Heating  this  base  with  caustic 
soda  solution  also  failed  to  render  it  permanently  soluble  in  ether  or  to 
affect  its  capability  of  crystallizing  from  ethereal  solutions.  On  re- 
examination of  the  caustic  soda  liquors  separated  in  the  various  repeti- 
tions of  this  experiment  we  found  that  after  having  been  exposed 
some  time  and  undergone  evaporation  they  presented  the  appearance  of 
37 
