150  Chemical  Examination  of  Cincho-^inine.{^'^-j^^^x^^^^''^' 
With  these  results  we  might,  under  ordinary  circumstances,  have 
been  satisfied  as  to  the  true  nature  of  the  nostrum.  But  we  had  set 
out  to  determine  quantitatively  the  amount  of  quinia  contained  in  it, 
and,  therefore,  only  considered  ourselves  well  prepared  to  make  intelli- 
gently a  quantitative  analysis. 
SERIES  OF  EXPERIMENTS  II. 
We  now  propose,  in  the  following,  to  give  the  results  of  our 
QUANTITATIVE   ANALYSIS  j 
but,  in  order  to  state  the  results  as  concisely  as  possible,  we  deem  it 
proper  to  make  the  following  preliminary  observations  : 
1 .  The  precipitates  were  all  obtained  with  as  small  a  quantity  of  pre- 
cipitant as  was  necessary  to  complete  precipitation,  and  these  (precip- 
itates) were  washed  with  as  little  of  the  washing  liquid  as  was  necessary 
to  completely  remove  soluble  contaminants. 
2.  77;*?  drying  of  precipitates  and  residues  was  conducted  in  a  water- 
bath,  at  a  temperature  of  180°  to  200°  F.,  as  long  as  they  lost  weigh^^ 
— generally  for  three  days,  and  sometimes  for  a  week  ;  the  filters  con- 
taining precipitates  being  enclosed  in  tared  and  covered  porcelain  cruci- 
bles. 
3.  The  filtering-paper  used  was  the  best  Swedish,  and  the  tare  of  the 
filters,  as  well  as  that  of  the  vessels  in  which  weighings  were  made, 
was  ascertained  after  subjecting  them  to  heating  on  the  water-bath  as 
long  as  they  lost  weight. 
4.  The  weighings  were  made  on  an  analytical  balance,  which  re- 
sponded to  the  one-tenth  part  of  a  milligram. 
5.  The  reagents  were  all  tested  for  their  purity  before  we  used  them, 
and  the  stronger  ether  was  that  manufactured  by  Dr.  E.  R.  Squibb. 
6.  The  cincho -quinine  used  in  this  series  of  experiments,  was  that 
described  as  sample  No.  2. 
Experiment  A. 
A  I . — 4.-1 18  grams  of  cincho-quinine  was  dried  ;  when  dried  it  weighed 
4*o66  grams  ;  it  had  therefore  lost  0*052  grams  =  1-262  per  cent. 
^lantitative  result  No.  i. — Cincho-quinine.^  when  dried  completely at  a 
te?nperature  of  l8o°  to  200°        lost  1*262  per  cent. 
A  2. — 5*0  grams  of  cincho-quinine  was  dissolved  in  water  acidulated 
with  hydrochloric  acid,  the  solution  was  precipitated  with  ammonia,  the 
precipitate  collected  on  a  filter,  washed,  dried  and  weighed.    It  weighed 
