Am.  Jour.  Pharm.  1 
Nov.,  1885.  ; 
Action  of  Papain. 
573 
It  will  be  noticed  that  A  was  partly  digested,  giving  a  precipitate 
on  boiling;  B  almost  completely  so,  since  there  was  no  precipitate  on 
boiling.  The  precipitate  by  acetic  acid,  soluble  in  excess,  was  hemial- 
bumose.    Both  A  and  B  were  slightly  bitter  after  digestion. 
The  point  naturally  suggested  by  these  experiments  was  that  papain 
might  be  utilized  in  preparing'an  artificial  peptonized  milk,  its  slower 
action  being  in  some  respects  an  advantage  over  pancreatic  extract,  in 
that  the  digestion  can  be  arrested  at  any  intermediate  stage  more  read- 
ily. In  some  conditions  of  disease,  it  ^seems  to  me  a  distinct  advan- 
tage to  employ  a  partly  digested  food,  because  some  work  is  left  for 
the  stomach  to  accomplish ;  in  others,  perhaps,  a  fully  peptonized  food 
would  be  more  useful. 
By  a  partly  digested'milk  is  meant  one  in  which  much  of  the  casein 
is  in  an  intermediate  stage,  namely,  as  metacasein  ^'  and  hemialbu- 
mose;  by  a  fully  digested  milk,  one  where  all  of  the  casein  has  been 
changed  into  peptone.  A  and  B,  in  the  experiments  quoted  above,  are 
types  of  the  two  stages. 
Milk  which  has  undergone  only  partial  digestion  is  not  very  bitter, 
but  has  the  disadvantage  that  it  causes  a  precipitate  on  boiling  after- 
wards. The  latter  result  may  be  obviated  by  making  it  sufficiently 
alkaline,  that  is,  adding  30  or  40  grains  of  bicarbonate  of  soda  to  the 
pint  of  milk.  It  is  only  slightly  different  in  appearance  from  ordi- 
nary milk.    The  wholly  digested  milk  is  more  bitter. 
The  following  practical  suggestions  may  be  made  regarding  the  pre- 
paration of  papainized  milk : 
A  pint  of  milk  is  taken,  and  a  quarter  of  a  pint  of  water;  add  an 
equal  volume  of  milk  to  the  water,  and  30  grains  of  bicarbonate  of 
soda,  and  boil ;  add  the  remaining  milk  to  the  hot  liquid.  The  result- 
ing temperature  varies  from  45°  to  55°C. ;  it  is  usually  about  48°C. 
(118°F.);  the  variation  depends,  of  course,  on  the  temperature  of  the 
cold  milk.  The  papain  must  now  be  quickly  stirred  in,  and  the  mix- 
ture covered  with  a  cosey,  and  placed  in  a  warm  place.  After  diges- 
tion it  is  boiled  to  stop  the  action.  This  method  does  as  well  for  pan- 
creatic as  for  papain  digestion ;  it  obviates  the  use  of  a  thermometer, 
and  so  can  readily  be  done  in  the  ward  or  sick  room. 
For  preparing  a  partly  digested  milk,  7  grains  of  papain,  with  an 
hour  and  a  half's  digestion,  is  quite  sufficient,  using  a  pint  of  milk  in 
the  manner  above  described;  for  the  more  complete  digestion,  10 
grains  for  two  hours  must  be  used. 
