338 
Story  of  the  Papaw. 
Am.  Jour.  Pharm. 
July,  1901. 
and  dark.  The  lighter-colored  and  best  products  are  produced  when 
the  coagulated  juice  is  removed  as  fast  as  it  exudes,  spread  out  thin 
and  quickly  dried. 
No  advantageous  method  of  gathering  the  milk  has  come  under 
my  observation.  Some  of  the  difficulties  of  the  present  usages  can 
be  imagined  by  the  recollection  that  in  some  cases  the  fruits  are 
from  20  to  30  feet  from  the  ground.  The  coagulation  allows  only  a 
small  yield,  requiring  constant  climbing  to  make  fresh  incisions. 
The  latex  yields  25  per  cent,  of  dried  material  (still  containing  6  to 
10  per  cent,  of  moisture).  Under  favorable  conditions  I  extracted  100 
grammes  of  latex  from  one  fruit.  One  gatherer  claimed  an  average 
yield  of  one  pound  of  dried  milk  from  each  tree  per  year,  though 
under  somewhat  adverse  conditions  it  required  fifty  trees  to  yield 
one  pound  of  dried  milk. 
OFFICE  OF  THE  MILK  AND  ENZYME. 
The  office  of  this  milk  in  the  economy  of  the  papaw  is  not  easy 
to  explain.  Parkin  (Pharmaceutical  Journal,  1578,  page  337)  states: 
"  The  most  important  function  of  such  a  latex  is  that  of  holding 
water  in  reserve."  This  seems  hardly  possible  in  respect  to  this 
plant  because  all  tissues  of  the  plant  are  filled  with  a  watery  fluid, 
so  much  so  that  they  flow  upon  cutting,  and  it  is  hardly  possible 
that  the  tree  is  dependent  upon  the  milky  juice  for  a  supply  of 
moisture.  The  native  observers  suggest  that  the  milk  has  to  do 
solely  with  the  ripening  of  the  fruit,  and  it  is  true  that  as  the  fruit 
ripens  it  is  in  all  parts  permeated  with  the  milk,  and  as  a  conse- 
quence the  starch  compounds  are  changed  to  sugar  ;  the  proteids 
are  peptonized  and  the  flavor  mellowed.  But  it  would  seem  to  be 
a  prodigious  waste  of  energy  if  this  ripening  action  was  the  only 
action  of  the  milk  and  its  enzyme  contents.11 
We  do  know,  however,  that  this  latex  is  the  carrier  of  enzymes, 
and  that  in  plant  life  certain  enzymes  play  an  important  part  in 
incorporating  material  for  the  growth  of  the  living  substance  or  of 
preparing  material  brought  to  it,  so  that  it  may  be  capable  of  such 
incorporation.     Again,  they  bring  about  decompositions  which 
11  Assuming  that  there  is  at  the  lowest  estimate,  100  ounces  of  latex  in  a 
tree,  we  would  have  twenty  ounces  of  dried  material  capable  of  converting 
about  3,000  pounds  of  proteids. 
