360 
PREPARATIONS   OF  CONIUM,  ETC. 
hemlock  leaves  do  possess  the  active  properties  commonly  as- 
cribed to  them. 
The  following  are  my  observations  upon  this  point: — 
Examination  of  the  dried  leaves  used  in  the  preparation  of  the 
tincture  above  referred  to. 
I.  February  11,  1867.  Took  one  ounce  avoirdupois  of  each 
of  the  two  samples  of  leaves,  separated  from  leaf-stalk  and  in 
coarse  powder,  and  packed  them  in  thin  layers  alternating  with 
layers  of  fine  sand  in  a  percolator.  f$x  of  water  containing  120 
grains  of  caustic  potash  was  poured  upon  them,  and  macera- 
tion allowed  for  24  hours.  The  aqueous  solution  was  then  dis- 
placed by  f^viii  of  dilute  alcohol  (equal  parts  of  rectified  spirit 
and  water),  and  maceration  allowed  for  24  hours  more.  The 
spirituous  fluid  was  next  displaced  by  water  acidulated  with  sul- 
phuric acid,  and  percolation  continued  as  long  as  the  running 
fluid  possessed  color,  f^xxii  of  very  dark  greenish-brown  fluid 
was  thus  obtained.  A  little  more  acid  was  added  to  produce 
exact  neutralization  of  the  alkali,  and  the  turbid  fluid  filtered. 
Chlorophyl  and  sulphate  of  potash,  destitute  of  conia  or  any  of 
its  salts,  remained  on  the  filter.  The  filtrate  was  evaporated 
over  a  water  bath  at  a  temperature  under  °160  F.,  until  about 
3V  of  dark  brown  extract,  of  treacly  consistence,  remained. 
While  still  warm,  this  was  rubbed  up  with  f^v  of  solution  of 
caustic  potash  (1  part  (HO,  RO),  3  parts  (HO) ).  A  very  faint 
odor  of  conia  was  evolved.  The  mixture  was  transferred  to  a 
long  tube,  and  shaken  at  intervals  with  an  equal  bulk  of  aether. 
The  aether  assumed  a  yellowish-green  color.  After  24  hours 
the  aetherial  solution  was  decanted,  and  the  extract  washed  with 
fresh  portions  of  aether  as  long  as  it  continued  to  dissolve  any- 
thing. The  mixed  aethereal  solutions  were  then  distilled.  Half 
a  grain  of  a  clear,  deep  sap-green,  thick,  oily  fluid,  lighter  than 
water,  remained.  It  possessed  a  mint-like  odor  mixed  with  that 
of  conia.  To  the  tongue  it  was  almost  as  bitingly  acrid  as  conia 
itself,  but  in  minute  quantity  it  produced,  like  oil  of  peppermint, 
a  cooling  sensation.  Its  taste  was  bitter,  and  it  possessed,  in  an 
intense  degree,  the  nauseous  flavor  of  the  dried  leaf  or  its  tinct- 
ure. It  was  in  fact  a  mixture  of  conia  and  the  oleo-resin  of  the 
plant,  colored  by  chlorophyl.    It  imparted  to  water  a  strong 
