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490  AN  ESSAY  ON  SASSAFRAS  OFFICINALE. 
It  is  evidently  a  derivative  of  the  tannic  acid  of  the  bark,  and 
exists  most  largely  in  the  exterior  layers  of  the  bark  which  have 
nearly  lost  their  astringency. 
The  large  proportion  found  by  Heinsh  proves  that  he  not  only 
analyzed  dry  old  bark,  but  probably  also  that  with  the  epidermis 
included.  I  have  before  alluded  to  the  fact  that  the  growing 
bark  is  nearly  white ;  whilst  the  same  bark,  simply  dried, 
becomes  cinchona-colored  exteriorly,  and  this  change  slowly 
extends  through  it.  The  following  experiments  were  made: — 
A  root  of  sassafras,  four  inches  in  diameter,  was  uncovered 
from  soil.  Four  vials,  one  filled  with  pure  glycerin,  another  with 
alcohol,  a  third  with  colorless  fixed  oil,  and  a  fourth  with  water, 
were  provided.  The  epidermis  was  quickly  scraped  oif,  and 
strips  of  the  bark  rapidly  removed  and  introduced  into  the  vials, 
so  as  to  be  completely  covered  with  the  several  liquids,  and 
before  any  change  of  color  by  atmospheric  action  had  occurred. 
On  standing  a  few  days  the  alcohol  had  acquired  quite  a  red- 
dish color,  which  increased  considerably  with  time.  The  gly- 
cerin was  affected  much  more  slowly,  but  gradually  it  was  dis- 
colored throughout,  extracting  the  tannin  from  the  bark,  and 
this  in  turn  being  discolored  by  the  air  acting  on  the  surface. 
The  bark  in  fixed  oil  was  a  long  time  intact,  but  at  present  it 
exhibits  portions  colored  brown.  The  watery  liquid  rapidly 
colored,  though  not  quite  so  soon  as  the  alcoholic.  Nitric  acid 
applied  to  the  fresh  bark  makes  a  brown  spot,  and  liquor  potassae 
a  dark  brown  one.  Either  of  the  solutions  above  noticed, 
except  the  oily  one.  are  colored  deep  red  brown  by  pqtassa. 
The  solutions  precipitate  gelatin  and  tartar  emetic,  and  are 
colored  dark  blackish-green  by  sesqui-chloride  of  iron.  The 
alkaline  solution,  though  dark-colored,  affords  but  little  precipi- 
tate with  hydrochloric  acid.  It  must  be  apparent  from  these 
results  that  sassafrid  is,  like  cinchonic  red,  a  derivative  of  tannic 
acid,  and  that  sassafras  tannin  exists  to  a  much  greater  extent 
in  the  fresh  bark  than  in  the  dried  commercial  specimens.  It 
must  also  be  apparent  that  carefully-dried  sassafras  bark  is  no 
mean  astringent  with  its  6  per  cent,  of  tannin  and  9  per  cent, 
of  sassafrid,  and  might  be  found  useful  in  some  forms  of 
diarrhoea. 
