558 
ON  PORTLAND  ARROW-ROOT. 
to  it,  together  with  some  iron  filings,  and  the  mixture  rapidly 
evaporated,  while  the  hydrogen  gas,  resulting  from  the  action  of 
the  acid  on  the  iron,  is  being  evolved.  The  lactate  is  thus  pre- 
served from  undergoing  peroxidation,  and  the  whole  of  the  li- 
quor may  be  exhausted  of  its  salt. 
An  equally  satisfactory  result  with  that  above  described  may 
be  obtained  by  double  decomposition,  but  as  it  is  necessary  in 
this  case  to  use  very  weak  solutions  of  sulphate  of  iron  and  lac- 
tate of  lime,  and  subsequently  to  concentrate  the  liquor  in  order 
to  effect  crystallization,  the  peroxidation  of  the  salt  must  be  pre- 
vented by  keeping  up  the  disengagement  of  hydrogen  in  the  man- 
ner already  described — Pharm.  Journ.  Aug.  1853,  from  Journ. 
de  Pharmacie. 
ON  PORTLAND  ARROW-ROOT. 
By  Mr.  T.  B.  Grotes. 
In  the  course  of  lectures  on  Materia  Medica  at  the  Pharmaceu- 
tical Society,  delivered  in  the  session  1850-51,  by  our  late  much 
lamented  Professor,  Dr.  Pereira,  he  mentioned  some  facts  relative 
to  the  manufacture  of  Portland  Arrow-root,  which  led  me  to  infer, 
that  he  considered  it  was  carried  on  to  a  considerable  extent  by 
the  inhabitants  of  the  Isle  of  Portland.  Living  within  a  short  dis- 
tance of  the  island,  I  have  thought  it  desirable  to  make  some  in- 
quiries to  ascertain  to  what  extent  it  is  carried  on  at  the  present 
time.  Dr.  Pereira  probably  derived  his  information  principally 
from  an  article  in  the  Transaction  of  the  Society  of  Arts,  vol.  xv. 
(1797,)  in  which  it  is  stated,  that  in  the  year  1797  the  gold  medal 
of  the  Society  was  awarded  to  Mrs.  Jane  Gibbs,  of  Portland,  for 
producing  a  sample  of  starch  fit  for  economic  purposes,  from  ma- 
terials unfit  for  the  food  of  man.  The  starch,  or  arrow-root,  as  it 
is  usually  called,  was  prepared  by  her  crushing  in  a  mortar  the 
corms  of  the  Arum  maculatum,  stirring  the  mass  with  water,  and 
straining  off  the  liquors,  from  which  the  fecula  was  allowed  to  sub- 
side ;  this  was  again  washed,  and  then  dried.  She  stated,  and  the 
statement  is  confirmed  by  the  then  Rector  of  the  island,  that  she 
had  in  her  possession  two  cwt.  of  the  starch,  and  was  ready  to  sup- 
ply any  quantity  of  the  same  whenever  required,  at  the  price  of 
lid.  per  lb.  Although  there  is  no  doubt  that  the  quantity  of  the 
starch  manufactured  was  much  greater  at  that  time  than  the  pre* 
