Am,juiu/;i9ohirrm"}  Story  of  the  Pap  aw.  341 
extract,  give  negative  results.  In  my  hands  this  extract  gave  no 
indication  of  tannin,  although  this  substance  has  been  reported  as 
present  in  the  milk.  The  acrid  resins  of  the  papaw  are  more  or 
less  extracted  by  alcohol,  but  more  completely  by  acetone.  The 
alcoholic  extract  is  acid  to  litmus. 
In  this  alcoholic  extract  the  presence  of  an  indicator  was 
observed.  When  the  extract  is  somewhat  .concentrated,  the  color 
becomes  a  beautiful  pink  which  is  destroyed  by  sodium  hydrate, 
added  to  saturation,  and  upon  concentrating  the  solution  to  dry- 
ness. The  color  is  not  restored  by  hydrochloric  acid.  (This  color 
substance  needs  further  study.) 
Ether  extract  (977  per  cent.)  is  nearly  colorless,  yielding  upon 
evaporation  a  residue  resembling  white  beeswax.  This  residue  is 
quite  soluble  in  chloroform,  but  only  partially  soluble  in  benzine  or 
alcohol.  (Soluble  in  hot  alcohol.)  The  aqueous  washings  of  this 
extract  give  an  acid  reaction  with  litmus  and  a  precipitate  with  lead 
acetate. 
Chloroform  extract  (H -20  per  cent.)  is  colorless  and  slightly  tur- 
bid. The  residue,  upon  evaporation,  is  wax-like  and  hard  (much 
resembling  the  residue  from  the  ether  extract).  This  residue  is 
partially  soluble  in  ether,  and  almost  insoluble  in  alcohol  and 
benzine.  The  aqueous  washings  from  this  extract  give  an  acid  reac- 
tion to  litmus. 
Acetone  extract  (5-98  per  cent.)  is  of  a  yellowish  color.  The 
evaporation  residue  has  a  pungent,  slightly  aromatic  odor  and  a 
dark  brown  color  resembling  the  extract  of  plants.  The  residue  is 
almost  wholly  soluble  in  alcohol,  chloroform  and  amylic  alcohol  ; 
but  slightly  soluble  in  ether,  and  insoluble  in  benzine.13 
As  the  substances  removed  from  the  latex  by  volatile  solvents 
were  in  the  nature  of  material  foreign  to  the  enzyme,  no  systematic 
examination  was  made.  These  solvents  do  not  seem  to  remove 
any  proteid  compounds  save  in  the  case  of  benzine,  which  extract 
gave  a  faint  proteid  reaction. 
As  a  result  of  a  rather  hasty  examination  of  these  extractions, 
we  may  assume  that  they  contain  coloring  matter ;  "  vegetable 
extractive  matter;"  hard  and  soft  waxes;  hard  and  soft  resins;  a 
13  The  alcoholic  and  acetone  extracts  give  slight  indications  of  the  presence 
of  nitrogenous  matter  by  the  soda-lime  process. 
