Anoctober  i9i4rm"}  Estimation  of  Morphine  and  Lloyd's  Reagent.  463 
solution  of  strychnine  in  water  acidified  with  sulfuric  acid  was  com- 
pletely precipitated  with  an  excess  of  Lloyd's  reagent,  and  the  pre- 
cipitate, after  thorough  washing  with  water,  dried  at  6o°.  A  portion 
of  the  precipitate  containing  about  0.2  g.  of  strychnine  was  sus- 
pended in  a  little  water  containing  an  excess  of  ammonia,  and  then 
repeatedly  shaken  out  with  successive  portions  of  chloroform,  using 
20  c.c.  of  the  latter  for  the  first  shaking  and  15  c.c.  each  time  after- 
wards. It  was  found  that  even  after  ten  consecutive  operations  the 
chloroform  did  not  ,  remove  all  of  the  alkaloid,  as  was  shown  by 
evaporating  some  of  the  chloroformic  extract  to  dryness,  taking  up 
the  residue  with  acidified  water,  and  testing  the  resulting  solution 
with  Mayer's  and  Wagner's  reagents,  both  of  which  continued  to 
give  a  heavy  precipitate.  Hence  by  this  method  it  is  extremely  dif- 
ficult quantitatively  to  recover  the  strychnine  from  a  solution  of  its 
salts  in  water.  Whether  other  methods  would  be  more  successful 
will  have  to  be  determined  by  further  experimentation. 
3.  Attempt  to  facilitate  the  removal  of  strychnine  from  the  pre- 
cipitate obtained  by  adding  Lloyd's  reagent  to  a  solution  of  a  salt  of 
the  alkaloid  in  water. 
The  precipitate  obtained  by  adding  an  excess  of  Lloyd's  reagent 
to  an  aqueous  solution  of  a  salt  of  strychnine  is  almost  perfectly 
tasteless,  though  it  contains  all  of  the  alkaloid  of  the  original  solu- 
tion. This  seems  to  suggest  the  veiw  that  the  reagent  forms  with 
the  alkaloid  an  exceptionally  stable  combination,  and  this  view  is 
further  strengthened  by  the  fact  that,  as  was  shown  above,  it  is  ex- 
tremely difficult  completely  to  recover  the  alkaloid  from  the  pre- 
cipitate. 
On  the  other  hand,  as  will  be  reported  later  by  Dr.  McGuigan,  the 
precipitate  acts  physiologically  very  much  like  strychnine  diluted 
with  an  inactive  substance,  showing  that  in  the  living  digestive  ap- 
paratus the  union  of  alkaloid  and  reagent  is  readily  disrupted.  Since 
it  was  reasonable  to  ascribe  this  disrupting  effect  to  the  digestive 
enzymes  of  the  animal  body,  experiments  were  made  in  order  to  de- 
termine whether  some  of  these  enzymes  would  show  the  same  dis- 
rupting effect  in  vitro.  If  this  were  so,  dilute  hydrochloric  acid  in 
presence  of  pepsin,  or  chloroform  in  presence  of  alkali  and  either 
ptyalin  or  trypsin,  readily  ought  to  extract  the  strychnine  from  the 
precipitate.  The  following  experiments  were,  therefore,  carried  out 
with  these  enzymes : 
Pepsin. — The  thoroughly  washed  and  dried  precipitate  obtained 
