208 
ON  PODOPHYLLUM  PELTATUM. 
residue  weighed  8.25  grs.,  it  evolved  ammonia  when  treated  with 
an  excess  of  caustic  potassa ;  and  Wackenroder's  observation, 
which  has  been  doubted  already  by  Liebig,  that  on  the  sponta- 
neous evaporation  of  a  solution  of  benzoic  acid  in  carbonate  of 
ammonia,  pure  benzoic  acid  is  separated  in  crystals,  is  thereby 
proven  to  be  incorrect.  Assuming  the  experiments  of  Berzelius, 
that  a  bibenzoate  of  ammonia  is  thus  formed,  to  be  correct  the 
above  71.67  per  cent,  or  7.167  grs.  of  C14H503,  would  require 
of  NH40  0.824  grs.  and  of  HO  0.285  grs.  making  the  required 
whole  weight  of  the  salt,  7.167+0.824+0.285=8.276,  with  which 
the  actual  weight  of  8.25  closely  agreed.  Accordingly  the  formula 
for  anhydrous  bibenzoate  of  ammonia  is  calculated  as  follows : 
NH40 
26 
9.96 
HO 
9 
3.45 
2C14H503 
226 
86.59 
NH40,HO,2C14H503 
261 
100.00 
and  8.25  grs.  of  bibenzoate  of  ammonia  as  found  above,  contain 
§^5^=7.143675  grs.  C14H503=  71.437  percent,  of  the  above 
benzoate  of  iron. 
This  experiment  verifies  on  the  one  hand,  the  above  formula 
for  the  neutral  benzoate  of  iron,  and  tends  to  prove  on  the  other 
hand  that  an  anhydrous  bibenzoate  of  ammonia  remains  behind 
on  evaporating  a  solution  of  benzoic  acid  in  ammonia,  at  a  tem- 
perature below  190°;  the  influence  of  a  higher  heat  had  not 
been  tried. 
Philadelphia,  March,  1860. 
ON  THE  BOOT  OF  PODOPHYLLUM  PELTATUM. 
Br  William  G.  Parrish. 
(Condensed  from  an  Inaugural  Essay.) 
The  author  set  out  in  his  investigations  with  the  intention  of 
determining  the  composition  and  efficiency  of  this  root,  as  ob- 
tained at  several  periods  of  the  year.  On  the  25th  of  June,  a 
pound  (7000  grains)  of  the  fresh  root  was  collected  and  dried ; 
the  dry  root  weighed  3076.5  grs.  Of  this,  1920  grains  was  pow- 
dered, and  extracted  by  percolation  with  alcohol,  the  tincture 
