« 
XSerf"  im  }  The  Assay  of  Jalap.  515 
sample,  "  winter  wheat  straight,"  does  not  show  any  signs  of  life 
at  the  present  time. 
The  results  are  quite  startling,  as  it  shows  that  the  stages  of 
some  of  these  small  forms  take  a  period  of  time  to  evolve  beyond 
our  present  knowledge,  also  that  they  did  not  need  any  oxygen  to 
sustain  them  as  the  jars  have  never  been  opened  since  the  flour 
has  been  placed  in  them,  showing  that  the  assertion  made  above,  that 
many  small  forms  live  to  a  more  or  less  extent  upon  gases  sup- 
posed to  be  poisonous,  had  a  foundation  of  truth.  Lastly,  that  in- 
stead of  one  of  the  species  known  as  grain-eaters  appearing,  that  a 
species  of  Psocidcc,  the  habits  of  which  are  very  little  known,  but  I 
do  not  recollect  that  they  have  ever  been  classed  as  flour-eaters 
before,  should  appear  in  such  immense  numbers. 
Note. — This  article  concludes  the  general  outline  of  the  divisions  used 
by  me,  and  I  shall  later  publish  a  detailed  account  of  each,  giving  descriptions 
and  illustrations  of  the  insects  and  examples  of  their  work. 
THE  ASSAY  OF  JALAP. 
By  Horace  North 
Analyst  with  Lehn  &  Fink,  New  York. 
Resin  of  jalap  is  defined  as  that  portion  of  the  drug  soluble 
in  alcohol  and  insoluble  in  water.  The  assay  of  jalap  for  resin 
is  properly  based  on  this  definition. 
Put  10  gms.  of  finely  powdered  jalap  in  a  shallow  porcelain 
basin  having  a  diameter  of  about  i6  cm.,  moisten  the  drug  with 
3  c.c.  of  water,  granulate  uniformly  with  the  aid  of  a  small  glass 
pestle,  transfer  to  a  sheet  of  paper  and  thence  into  a  300  c.c. 
Erlenmeyer  flask.  Add  51  c.c.  of  95  per  cent,  alcohol,  connect 
the  flask  with  a  reflux  condenser  and  heat  in  a  water-bath  so  that 
the  alcohol  boils  gently  for  about  one  hour.  Lay  a  pledget  of 
absorbent  cotton  in  the  bottom  of  a  sHghtly  conical  percolator, 
saturate  with  alcohol,  and  press  a  perforated  porcelain  plate  firmly 
down  upon  the  cotton  until  the  excess  of  alcohol  has  drained.  Place 
the  dish  in  which  the  drug  was  granulated  on  a  water-bath,  kept 
warm  over  a  low  flame,  and  support  the  percolator  above  the  dish. 
Remove  the  flask  from  the  water-bath,  cover  with  a  porcelain 
