ON  COPALCHE  BARK. 
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1.  The  solvent  power  of  glycerin  lies  between  that  of  water 
and  alcohol. 
2.  Substances  are  in  general  the  more  soluble  in  glycerine, 
the  more  they  are  so  in  alcohol,  with  some  exceptions,  however. 
3.  In  most  cases  alcohol  is  a  better  solvent  than  glycerin,  ni- 
trate of  strychnia  excepted. 
4.  Glycerin  is  a  soft,  mild  solvent,  deserving  the  preference 
to  alcohol  in  many  cases  of  external  application. 
5.  Independent  of  the  water  it  contains,  glycerin  of  itself 
has  solvent  powers,  as  there  are  some  substances  soluble  in  it 
that  are  insoluble  in  water,  and  anhydrous  glycerin  dissolves 
iodide  of  potassium  as  well  as  that  of  28°. 
ON  COPALCHE  BARK. 
By  John  Eliot  Howard,  Esq. 
I  beg  to  present  to  the  Pharmaceutical  Society  a  specimen  of 
Copalche  Bark,  the  produce,  according  to  Pereira,  of  Croton 
Pseudo-China,  and  described  by  him  in  his  Elements  of  Materia 
Medica,  vol.  ii.,  pt.  1,  p.  1283.  It  is  part  of  a  recent  importa- 
tion of  about  sixty  bales,  brought  from  Puntas  Arenas,  in  the 
gulf  of  Nicoya.  From  the  situation  of  this  port,  it  is  probable 
that  the  bark  is  the  produce  of  some  part  of  Costa  Rica.  The 
specimen  is  evidently  identical  with  Pereira's  specimen  of  Quilled 
Copalche,  which  is  deposited  in  the  Museum  of  the  Society.  The 
odor  in  burning  is  that  of  Cascarilla,  and  in  both  these  specimens 
the  appearance  of  the  singularly  indented,  resinous-looking  derm 
where  denuded  (especially  when  observed  with  a  magnifying 
glass,)  is  a  highly  characteristic  feature  of  the  species.  It  ap- 
pears, as  Pereira  indicates,  to  be  the  sort  figured  by  Goebel  and 
Kunze,*  and  ascribed  (owing  to  a  suggestion  of  Humboldt)  to 
the  Croton  suherosum.  This  is  more  probably  the  origin  of 
Pereira's  Corky  Copalche  bark,  which  was  described  by  my  friend 
Dr.  Stark,  in  1849,  from  specimens  which  I  had  the  pleasure  of 
forwarding  to  him.  This  latter  kind  is  corky  in  the  extreme, 
which  is  not  the  case  with  the  Quilled  Copalche  now  before  us. 
*  Goebel  and  Kunze  Pharmaceut.  Waarenk. 
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