336 
Story  of  the  Pap  aw. 
Am.  Jour.  Pharm. 
July,  1901. 
THE  STORY  OF  THE  PAPAW. 
By  F.  B.  Kilmer. 
{Continued from  page  285. ) 
THE  MILK  OF  THE  PAPAW. 
Trees  that  give  milk  are  plentiful  in  the  tropics.  The  native 
name  for  the  papaw  is  "  lechoso  "  (a  producer  of  milk).  When  an 
incision  is  made  in  the  bark  of  any  part  of  the  tree  or  in  the  fruit 
rind,  a  limpid,  milk-like  liquid  exudes  very  freely.  It  is  slightly 
more  dense  than  water,  and  in  contact  with  the  air  quickly  coagulates 
and  closes  the  incision.  This  coagulation  is  a  rather  notable  phe- 
nomenon. 
For  the  fraction  of  a  minute  the  liquid  flows  as  though  a  milk 
bottle  were  uncorked,  and  one  imagines  that  gallons  will  run  with- 
out stopping,  but  suddenly  it  ceases.  On  examination  it  is  found 
that  the  milk  is  coagulated  for  a  considerable  distance  within  the 
glands.  I  am  quite  firmly  convinced  that  this  action  is  due  to  the 
presence  of  a  clotting  enzyme.  This  assumption  is  made  probable 
by  the  fact  of  the  quite  ur  iversal  presence  of  pectin  in  plants,  and 
further  from  the  fact  that  I  have  proven  the  presence  of  calcium 
salts  and  pectic  compounds  in  the  latex  of  the  papaw.  This  state- 
ment is  further  strengthened  by  my  observation  that  the  latex  of 
the  papaw  will  coagulate  the  juice  (neutral  or  alkaline)  ot  certain 
other  plants.  The  presence  of  rennin  ferment  in  the  latex  of  the 
papaw  is  noted  elsewhere  in  this  paper.  Its  behavior  is,  in  many 
respects,  unlike  that  of  the  jelly-forming  enzyme  here  noted,  and, 
while  further  examination  of  fresh  material  is  needed  before  making 
any  fuller  statement,  I  think  I  am  sare  in  announcing  that  we  may 
add  the  papaw  latex  to  the  list  of  plant  juices  in  which  the  pectase 
ferment  has  been  noted. 
The  odor  of  the  fresh  milk  is  pronounced,  and  not  unlike  that  of 
the  latex  of  the  india-rubber  tree,  and,  on  the  whole,  is  a  disagree- 
able one,  suggestive  ot  decayed  meat.  The  taste  is  somewhat  bit- 
ter, rather  markedly  astringent  and  acrid.  When  dried  by  artificial 
heat  the  ferment  power  is  weakened  or  lost,  if  dried  in  the  sun  it 
retains  its  activity  and  about  75  per  cent,  of  moisture  is  separated. 
This  milky  emulsion  seems  to  be  secreted  for  the  most  part  in 
fairly  large  vessels  (readily  observable  by  a  pocket  lens),  which  lie 
just  under  the  epidermis  in  every  part  of  the  plant.    In  the  ripened 
