ON"  HOWARDIA  FEBRIFUGA. 
449 
other  respect,  however,  did  it  appear  to  agree  with  the  alkalies 
of  the  true  cinchonas  ;  and  when  submitted  under  the  microscope 
to  the  tests  pointed  out  by  Herapath,  it  exhibited  none  of  the 
remarkable  peculiarities  which  are  noticed  with  quinia,  cinchonia 
and  quinidia.  The  acetate  crystallized  under  the.  microscope,  but 
exhibited  no  phenomena  of  polarization. 
It  is  not,  however,  to  this  alkali  that  the  bark  of  Howardia 
owes  its  medicinal  properties,  but  rather  to  another  substance 
which  forms  nearly  twelve  per  cent,  of  the  weight  of  the  barks. 
This  is  soluble  in  alcohol,  but  not  in  ether  ;  has  a  feeble  alkaline 
reaction,  and  seems  to  be  combined  with  a  very  characteristic 
coloring  matter ;  a  coloring  matter  which  may  be  united  to  oxide 
of  tin,  and  which,  when  isolated  by  sulphuric  acid,  forms  with 
alcohol  a  brilliant  yellow  solution,  becoming  brown  by  evapora- 
tion and  exposure  to  the  air.  In  the  latter  case  it  undergoes  a 
true  oxidation,  and  gives  rise  to  phenomena  which  indicate  the 
presence  of  several  different  substances.  There  appears,  how- 
ever, to  be  one  only  which  produces,  in  its  different  stages  of  oxida- 
tion, all  the  different  shades  between  golden  yellow  and  brown 
black,  which  is  remarked  in  this  bark.  The  sixty  parts  of  the 
bark  which  were  insoluble  in  boiling  water,  when  treated  by 
ammonia  yielded  about  one-tenth  of  its  weight,  and  the  residue 
boiled  in  water  and  hydrochloric  acid,  furnished,  in  addition,  four 
parts  of  coloring  matter  in  combination  with  lime. 
The  woody  matter  remaining  gave,  by  incineration,  a  consider- 
able proportion  of  lime  and  magnesia,  with  some  traces  of  potassa 
and  soda. 
The  alkali  and  the  bitter  principle  appear  to  have  the  same 
relations  as  biberine  and  siperine  from  the  Greenheart  bark, 
(Nectandra  Rodisei.)  It  may,  perhaps,  be  that  the  bitter  prin- 
ciple is  a  compound,  a  fact  which  it  is  not  yet  possible  to  deter- 
mine on  account  of  the  small  amount  of  the  bark  which  has  been 
submitted  to  examination.  The  taste  of  the  alkali  is  bitter,  with 
an  after  taste  of  astringency  which  is  likewise  found  in  the  other 
principle. — Ann.  des.  Scien.  Nat.  iv.  Ser.  t.  1,  No.  2. 
29 
