544 
EXAMINATION  OF  KINO. 
tate  the  concentrated  alcoholic  decoction  of  kino  with  suhacetate 
of  lead,  added  drop  by  drop  until  a  few  drops  of  pure  water  filtered 
out  of  the  brownish-red  jelly  which  was  formed  ;  the  mass  was  then 
digested  in  very  cold  distilled  water,  until  it  began  to  communi- 
cate a  color  to  it,  when  it  was  poured  off  and  filtered  rapidly. 
This  liquid  contained  a  greater  part  of  the  tannic  acid.  This  pro- 
cess may  be  supposed  to  consist  either  in  a  combination  of  the  ace- 
tate of  lead  with  the  red  coloring  matter  of  the  kino  only,  and  that 
the  tannic  acid  is  mechanically  retained  until  the  alcoholic  jelly  is 
saturated  with  water,  or  that  both  substances  form  lead  salts,  and 
that  the  contact  with  water  causes  a  decomposition,  in  consequence 
of  which  tannic  acid  is  set  free.  It  is  advisable  to  use  a  slight 
excess  of  subacetate  of  lead  rather  than  not,  for  the  quantity  of 
tannate  of  lead  dissolved  in  that  case  is  insignificant  compared 
with  the  freedom  of  the  tannic  acid  from  coloring  matter. 
After  the  addition  of  a  sufficient  quantity  of  moist  hydrated  ox- 
ide of  lead,  the  slightly  reddish  colored  tannate  of  lead  was  sepa- 
rated and  introduced  into  a  retort,  when  it  was  dried  in  a  stream 
of  hydrogen  gas.  Hennig  obtained  from  two  analyses  the  follow- 
ing results,  corresponding  with  Berzelius's  formula  for  tannic  acid 
c 
14 
53.16 
52.7 
H 
10 
3.71 
39 
0 
8 
43.13 
4.35 
The  analysis  of  the  lead  salt  gave 
C 
18 
34.02 
33.00 
34.55 
H 
18 
5.67 
5.93 
5.92 
0 
10 
25.19 
26.67 
25-23 
PbO  • 
1 
35.12 
34.40 
33.30 
The 
elements  are  here 
nearly  in 
the  same  proportions  as  in 
Rochleder's  catech 
uic  acid 
I,  and  the  difference  may  be 
owing  to  an 
admixture  of  acetic  acid. 
Hennig  is  of  the  opinion  that  the  red  coloring  matter  so  inti- 
mately combined  with  the  tannic  acid,  may  be  obtained  best  by 
treating  the  aqueous  infusion,  from  which  the  above-mentioned  yel- 
low deposit  has  separated,  with  finely  powdered  hydrated  oxide  of 
lead,  until  the  liquid  is  nearly  decolorized.  The  substance  ob- 
tained from  the  lead  compound  in  the  ordinary  manner,  gave  on 
analysis 
