320 
Tannins  of  Some  Ericacece. 
Am.  Jour.  Pharm. 
June,  1896. 
Product  from 
Tannin  of 
Calcium 
Hydrate. 
Ferric 
Chloride. 
Ferric 
Acetate. 
Ferrous 
Sulphate. 
Chimaphila  
f  Slight  rpd-1 
1    dening.  J 
Green  ppt. 
1     PPt.  J 
Greenish  ppt. 
Trailing  arbutus    .  .  . 
Brownish,  ppt. 
Green  ppt. 
Green  ppt. 
Plum  ppt. 
(Red  ppt.  and  1 
(    color.  J 
Green  ppt. 
Green  ppt. 
Plum  ppt. 
Mountain  laurel  .... 
(Slight  red} 
1     color.  J 
Plum  ppt. 
Plum  ppt. 
Greenish  ppt. 
[Greenish- 
(    j-ellow  ppt. 
Olive-brown 
ppt. 
Olive-brown  "1 
ppt.  f 
Plum  ppt. 
No  change. 
J   W  li  \  C  U1UW11 
I  ppt. 
Oli vc-torowti  ) 
ppt.  ; 
Plum  ppt. 
(  Purple  color, 
<    changing  to 
(  brown. 
Red  color,] 
changing  to  > 
brown.  ) 
(Blue  color, 
■I  changing  to 
(.  green  and  red. 
(Reddish  or) 
\    brown  ppt.  J 
Green  color. 
No  reaction. 
The  foregoing  chemical  investigations  not  having  given  as  defi- 
nite knowledge  of  the  exact  nature  of  the  tannins  as  the  author 
desired,  a  quantity  of  the  principle  from  each  of  the  drugs  was  sub- 
mitted to  combustion  in  order  to  determine  the  ultimate  compo- 
sition of  the  substances- as  the  last  recourse  in  the  attempt  to  classify 
them.  The  combustions  were  performed  with  copper  oxide,  in  an 
open  tube  through  which  a  stream  of  oxygen  was  conducted.  The 
results  were  calculated  into  percentages,  in  the  usual  way;  they 
were  as  follows : 
Trailing  Arbutus.     Gaultheria.    Mountain  Laurel.  Oak  Bark. 
Carbon                         .  59-26            5973  6roo  5979 
Hydrogen  4-88              4*87  5*33  5*o8 
Oxygen  35*86             35-40  33*67  35-13 
Uva  Ursi.  Manzanita.  Gallotannic  Acid. 
Carbon  52*88  54*71  52*17 
Hydrogen                                             4*26  4*44  3  10 
Oxygen  42*86  40*85  44-73 
Chimaphila. 
1.  II.  III. 
Carbon                                               57*54  58*22  57-82 
Hydrogen  5*69  5*58  5 '45 
Oxygen  3677  36-20  36*73 
The  average  percentage  composition  of  the  tannins  from  the 
barks  of  nine  species  of  oak,  as  given  on  page  93  of  Volume  II  of 
"  The  Tannins,"  by  Henry  Trimble,  as  also  the  percentage  composi- 
