546  Goa-powder  and  Chrysophanic  Acid.   { Am^0°vu,r- J7h7arm' 
Fayrer,  of  Calcutta,  which  was  published  in  the  "  Medical  Times  and 
Gazette,"  on  the  treatment  of  Indian  ring-worm  by  Goa-powder.  Dr. 
Fayrer  states  that  in  the  treatment  of  certain  cutaneous  diseases  he 
found  no  remedy  as  certainly  effective  as  a  secret  preparation  sold  in 
small  vials  by  the  chemists  of  Calcutta  and  Bombay  under  the  name  of 
"  Goa-powder." 
In  1875,  Dr.  J.  F.  DaSilva  Lima  describes  the  Araroba,  a  tree  grow- 
ing in  Brazil,  belonging  to  the  leguminosae  as  furnishing  a  powder  known 
in  Brazil  as  Po'  de  Bahia,  and  in  the  province  of  Bahia  as  Araroba 
powder,  as  a  powerful  remedy  for  cutaneous  affections.  Dr.  Lima 
believes  in  and  endeavors  to  establish  the  identity  between  Goa  and 
Araroba. 
In  April,  1875,  Mr.  E.  M.  Holmes  read  a  paper  before  the  Pharm- 
aceutical Society  of  Great  Britain  "  On  the  identity  of  Goa-powder  and 
araroba  or  chrysarobin." 
In  March,  1877,  Prof.  Attfield  showed  that  chrysarobin  contained 
from  80  to  84  per  cent,  of  chrysophanic  acid. 
The  botanical  source  of  Goa  is  not  certainly  known  ;  by  some  it  has 
been  referred  to  a  lichen,  by  others  to  a  leguminous  plant ;  again,  it 
has  been  referred  to  different  species  of  centrolobium  and  caesalpinia, 
growing  in  Brazil,  and  which  are  said  to  yield  large  quantities  of  chry- 
sophanic acid.  Cuttings  from  the  plant  or  tree  yielding  goa  have  been 
sent  to  the  Royal  Botanical  Gardens  at  Edinburgh,  and  in  time  we  will 
have  a  more  certain  knowledge  of  its  botanical  source. 
As  the  drug  is  a  product  of  South  America,  the  question  naturally 
suggests  itself  how  it  came  to  be  introduced  into  Europe  by  way  of 
India.  ^  The  solution  of  the  query  is  to  be  found  in  the  fact  that  the 
commerce  of  Brazil,  when  under  the  control  of  Portugal,  was  carried 
on  by  the  mother-country  chiefly  between  her  South  American  pos- 
sessions and  her  colonies  in  the  East,  and  Goa,  on  the  Malabar  coast, 
was  formerly  the  capital  of  the  Portuguese  dominions  in  India. 
Chrysophanic  acid,  which  forms  so  large  a  portion  of  Goa-powder, 
was  discovered  by  Schrader  in  1819.  He  named  it  "  Resinous  yellow 
of  wall  lichens"  (Parmelia  parietina).  Messrs.  De  LaRue  and  Mlil 
ler  subsequently  obtained  it  from  rhubarb-root,  in  which  it  forms  the 
yellow  coloring  matter.  It  is  also  found  in  the  yellow-dock  and  other 
plants. 
Chrysophanic  acid  dissolves  in  1125  parts  of  85  per  cent,  alcohol  at 
