604 
The  Tannin  of  Some  Acorns. 
/Am.  Jour.  Pharm. 
1   November,  1896. 
The  cupule  usually  attracts  attention  on  account  of  its  astring- 
ency,  and  it  will  be  observed  that  when  it  is  collected  during  Sep- 
tember it  is  valuable ;  but  the  difficulty  of  collection  from  the  trees 
would  be  an  industrial  drawback,  and  after  it  falls  the  deterioration 
is  considerable,  as  shown  in  that  collected  on  October  4th,  which 
collection  was  from  those  which  had  fallen  to  the  ground. 
A  quantity  of  the  tannin  was  extracted  from  the  cupules  of  the 
chestnut  oak,  and  purified.  It  resembled,  in  physical  and  chemical 
characters,  that  of  all  the  oak  barks  heretofore  examined  by  me,  by 
giving  a  green-  color  and  precipitate  with  salts  of  iron,  a  precipitate 
with  bromine  water,  and  a  pink  color  with  calcium  hydrate.  On 
combustion  it  yielded  the  following  percentages,  which  are  com- 
pared with  the  average  composition  of  the  tannins  obtained  by  me 
frcm  nine  species  of  oak  bark: 
Average  Obtained 
Tannin  from  on  the  Tannins 
Cupules  of  from  Nine  Species 
Chestnut  Oak.  of  Oak  Bark. 
Carbon   59'93  59  79 
Hydrogen   576  5*08 
Oxygen   34-3*  35^3 
IOO'OO  IOO'OO 
The  following  are  the  percentages  of  tannin  found  in  the  cupules 
of  a  number  of  other  oak  species  : 
Date  of 
Collection. 
Quercus  alba,  L   Aug.  29 
Quercus  macrocarpa,  Michx.,     Aug.  31 
Quercus  rubra,  1,  {  "^"U^'  ^° 
^  I  Oct.  4 
Quercus  velutina,  ham.  .  .  .     Aug.  30 
Quercus  coccinea,  Wang.  .  .     Aug.  29 
Quercus  digitata,  Marsh .    .  .     Oct.  18 
Tannin 
Ash  in  Dry 
in  Dry- 
Moisture. 
Substance. 
Substance 
40-85 
2*24 
1 1 75 
56'14 
5 '59 
10*37 
28-86 
277 
5'27 
7-66 
276 
4"55 
I3-85 
3i6 
777 
21-03 
1-99 
12-66 
46-52 
4*34 
5*98 
I  am  indebted  to  J.  C.  Peacock  for  the  preparation,  purification 
and  ultimate  analyses  of  the  tannin  from  the  cupules  of  the  chest- 
nut oak ;  and  to  G.  H.  Maghee  for  the  estimation  of  the  tannin  in 
the  cotyledons  of  chestnut  oak,  and  for  repeating  my  estimations  in 
a  number  of  other  cases,  thereby  confirming  them.  The  hide-pow- 
der process  was  used  in  all  the  estimations. 
