176  Periodide  Test  for  Alkaloids.         { Amk^i9^arm" 
attached  to  a  piece  of  glass  tubing,  H,  in  the  side  of  which  a  hole 
about  6  mm.  in  diameter  has  been  blown.  The  jet,  F,  is  fixed  firmly 
in  this  tube  by  means  of  the  perforated  rubber  stopper  /.  A  piece 
of  copper  wire  provided  with  a  hook  is  attached  to  the  tube  H,  so 
that  the  latter  may  be  suspended  from  the  wire  /,  which  is  attached 
to  the  flask.  The  end  of  the  T  piece  A,  is  connected  with  the  com- 
pressed air  main  by  means  of  rubber  tubing.  When  the  compressed 
air  is  turned  on,  it  passes  through  the  horizontal  portion  of  T  piece 
A,  then  through  T  piece  C,  and  leaves  the  apparatus  at  the  hole  H. 
When  the  apparatus  is  in  use  the  thumb  of  the  right  hand  is  placed 
over  H,  the  compressed  air  then  passes  through  the  vertical  limb  of 
T  piece  A,  into  the  flask,  and  forces  the  water  through  the  jet  F. 
Very  little  compressed  air  is  required  by  this  apparatus.  If  the 
air  is  turned  on  in  the  morning,  the  apparatus  may  be  used  at  any 
time  by  simply  placing  the  thumb  over  H.  The  force  of  the  jet 
may  be  easily  regulated  by  allowing  part  of  the  air  to  escape  at  H. 
This  apparatus  is  very  convenient  for  washing  precipitates,  etc., 
as  the  jet  of  water  may  be  sent  in  any  direction  by  a  slight  turn  of 
the  wrist. 
Analytical  Department, 
Parke,  Davis  &  Co.,  Detroit. 
A  NOTE  ON  THE  PERIODIDE  TEST  FOR  ALKALOIDS. 
By  A.  H.  Clark. 
In  the  course  of  the  alkaloidal  assay  of  crude  drugs  one  is  con- 
stantly testing  for  the  presence  of  alkaloids  to  determine  whether 
or  not  extractions  are  complete.  Of  the  numerous  tests  employed, 
a  solution  of  iodine  in  potassium  iodide  and  water  is  very  common 
because  of  its  great  sensitiveness,  simplicity  of  preparation,  and  ever 
readiness.  This  solution,  as  is  well  known,  when  added  to  an  acidu- 
lated solution  of  an  alkaloid  yields  a  brownish-red  precipitate. 
On  one  occasion  when  extracting  an  ethereal  solution  of  an 
alkaloid  with  normal  acid  I  attempted  to  use  this  test  to  determine 
when  all  of  the  alkaloid  was  extracted  from  the  ether.  After  shak- 
ing out  with  eight  or  ten  portions  of  acid  and  still  obtaining  a  pre- 
cipitate indicating  incomplete  extraction,  I  concluded  that  something 
was  wrong  and  began  a  search  for  the  trouble.  This  search  (the 
details  of  which  I  will  omit)  revealed  the,  to  me,  surprising  fact  that 
water  saturated  with  ether  and  then  acidulated  gives  with  iodine 
