POPULIN. 
259 
We  now  placed  a  male  frog  in  one  four-hundredth  part  of  a 
grain  of  the  acetate  of  strychnia,  dissolved  in  six  drachms  of 
water.    In  three  hours  and  a  half  it  became  violently  tetanic. 
The  fresh  frog  is,  therefore,  at  this  season,  stry-chnoseopic  of 
one  four-hundredth  part  of  a  grain  of  the  acetate  of  strychnia^ 
and  probably  to  a  much  minuter  quantity,  which  ulterior  experi- 
ments must  show. 
In  the  two  other  experiments,  the  one  five-hundredth  and  the 
one  one-thousandth  of  a  grain  of  the  acetate  of  strychnine  were 
detected.—  Lancet,  in  Pliarm.  Jour. 
POPULIN. 
The  crystalline  substance  obtained  by  Bracconot  in  1830, 
from  the  bark  and  leaves  of  Populus  tremula,  consists  of — 
Carbon  56.49  56.49  56.36  56.34 
Hydrogen     6.39  6.13  6.29  6.10 
Oxygen      37.12        37.38        37.35  37.56 
And  its  composition  ma,y  be  represented  by  the  formula  C40  H96 
O20j  or  by  C4t)  H22  01G  +  4  HO;  since  by  heating  at  212°  F.,. 
it  loses  8.43  per  cent,  water  ;  and  four  equivalents  HO  corres- 
pond with  8.45  per  cent. 
Dilute  hydrochloric  acid  dissolves  populin,  and  at  212°  F. 
decomposes  it,  forming,  together  with  benzoic  acid  and  grape 
sugar,  a  resin  which  melts  in  boiling  water,  and  has  all  the  char- 
acters of  saliretin.  When  populin  is  heated  with  a  mixture  of 
sulphuric  acid  and  bichromate  of  potash,  it  evolves  hydruret  of 
salicyle,  which  is  inconsistent  with  the  view  that  populin  is  a 
conjugate  .compound  of  saliretin,  grape  sugar,  and  benzoic  acid. 
Piria  considers  it  to  be  a  compound  of  saligenin,  grape  sugar, 
and  benzoic  acid  ;  and  that  the  saligenin  separated  in  its  decom- 
position is  resolved  by  the  further  action  of  acids  into  saliretin  : 
C40 IL,  0M  +  4  HO  =  014  II,.  04  +  Cu  H»  04  +  Ow  H12  012 
Populin        Benzoic  acid      Saligenin     Grape  sugar 
Under  the  influence  of  decomposing  casein,  at  a  moderate  tem- 
perature, and  in  contact  with  carbonate  of  lime,  populin  is  de- 
