Am.  Jour.  Pharm. 
April,  1893. 
Canaigre  Tannin. 
163 
dry  root)  8  per  cent,  moisture,  44 7  per  cent,  total  extract,  30  5 
per  cent,  tannic  acid,  68  23  per  cent,  purity. 
"  It  is  of  great  interest  to  us  to  know  that  the  cultivated  root  is 
at  least  equal  to  the  wild,  and  we  see  no  reason  why  the  percentage 
of  tannin  should  not  be  increased  by  judicious  selection."  1 
Some  of  the  green  roots  sent  by  Professor  Collingwood  have 
been  growing  indoors  since  last  September  and  the  growth  has 
been  satisfactory. 
The  chief  object  of  this  paper  is  to  give  the  results  of  a  more 
extended  study  of  the  tannin. 
Preparation  and  Purification. — Two  methods  of  preparation  were 
tried,  one  by  percolation  with  commercial  ether,  and  the  other  by 
percolation  with  cold  water.  The  product  from  the  ether  extrac- 
tion was  found  to  be  very  difficult  to  purify  from  the  associated 
yellow  coloring  matter,  so  that  water  was  adopted  as  the  menstruum. 
The  diluted  aqueous  percolate  was  divided  into  two  equal  parts. 
One  portion  was  completely  precipitated  with  lead  acetate,  the  other 
was  then  stirred  into  it,  and  the  whole  filtered,  whereby  a  yellow  fil- 
trate was  obtained.  The  tannin  in  the  filtrate  was  removed  by 
agitation  with  acetic  ether.  By  distilling  off  the  latter  under  dimin- 
ished pressure,  the  tannin  was  obtained  as  a  porous  yellow  residue. 
The  thoroughly  dried  and  finely  powdered  tannin  was  treated 
with  absolute  ether  to  remove  coloring  and  crystalline  substance. 
The  latter  was  obtained  in  acicular  crystals  and  was  almost  entirely 
protocatechuic  acid. 
The  treatment  with  absolute  ether  proved  quite  successful  in 
removing  the  coloring,  but  it  is  obvious  that  the  absorption  of 
moisture  must  be  guarded  against  or  tannin  will  dissolve. 
The  ether  washed  tannin  was  dissolved  in  ether  containing  just 
sufficient  alcohol  to  effect  solution,  the  latter  was  filtered  and  then 
distilled  to  dryness  in  a  partial  vacuum  when  a  porous  yellow  residue 
remained.  This  was  employed  in  the  subsequent  work  on  the 
tannin.  Attempts  were  made  to  get  rid  of  the  yellow  coloring 
matter  by  precipitation  of  the  tannin  with  lead  acetate  and  washing 
1  Since  writing  this  paper,  Bulletin  No.  7  of  the  Arizona  Agricultural  Experi- 
ment Station  has  been  received  from  Professor  Collingwood.  This  pamphlet 
of  40  pages  is  devoted  entirely  to  Canaigre,  under  five  headings,  as  follows  : 
(1)  Historical  Sketch;  (2)  Botanical  Characteristics;  (3)  Chemical  Exami- 
nation ;  (4)  Cultivation  ;  (5)  Conclusions. 
