364 
Theory  of  Absorption  of  Fat. 
( Am.  Jour.  Pharm. 
I       July,  1890. 
absorbed,  it  is  reconverted  into  fat.  The  fact  that  fats  are  split  up 
in  the  intestine,  and  that  the  organism  can  form  fat  out  of  fatty 
acids  are  points  in  favor  of  this  theory.  In  this  second  theory,  the 
porter-like  activity  of  the  cells,  fixed  or  wandering,  is  dispensed 
with. 
A  third  theory,  the  one  held  at  present  by  most  physiological 
chemists,  maintains  that  the  main  part  of  the  fat  is  absorbed  as 
neutral  fat  in  the  form  of  an  emulsion,  but  that  to  form  this  emul- 
sion, part  of  the  fat  must  have  been  previously  broken  up.  An  alka- 
line carbonate  will  not  form  an  emulsion  with  neutral  fat,  but  forms 
a  soap  at  once  with  free  fatty  acids.  Suppose  a  neutral  fat  inti- 
mately mingled  with  fatty  acid  and  acted  on  by  an  alkaline  carbon- 
ate ;  everywhere  between  the  molecules  of  neutral  fat  will  lie 
molecules  of  soap,  and  the  result  will  be  an  exceedingly  fine  emul- 
sion. All  that  is  required  is  first  a  breaking  up  of  the  fat  to  a  slight 
extent,  so  as  to  afford  fatty  acids  which  are  saponified  by  the  various 
alkaline  secretions  poured  into  the  intestine.  These  are  the  secre- 
tions of  the  follicles  of  Lieberkiihn  (succus  intestinalis)  the  bile,  and 
pancreatic  juice.  The  intestinal  juice,  according  to  most  authors, 
excepting  Schiff  and  Hoppe-Seyler,  acts  on  the  fat;  and  Bunge,  from 
its  richness  in  carbonate  of  soda,  puts  stress  on  its  action  in  neutral- 
izing the  acids  of  the  alimentary  tract  and  emulsifying  fat.  The 
bile,  beyond  question,  assists  in  the  absorption  of  fat,  but  how  it  acts 
is  not  yet  decided.  In  its  absence  the  absorption  is  lessened  but 
not  stopped.  What  re  does  the  pancreas  play  ?  The  whole  pith 
of  the  paper  lies  in  the  answer.  The  pancreas  was  completely 
removed  in  dogs  by  the  author  and  Mering,  and,  with  the  excep- 
tion of  milk,  all  other  fatty  substances,  e.  g.,  butter,  olive  oil,  yolk  of 
egg,  fat  of  meat,  even  if  given  in  the  small  quantities  of  25  to  30 
grains  per  day,  were  completely  recovered  from  the  faeces.  When 
the  food  was  mixed  with  fresh  pancreas  of  pig,  the  greater  portion 
of  the  fat  was  absorbed.  It  follows  from  this  that,  for  the  absorption 
of  fats,  the  secretion  of  the  pancreas  is  indispensable,  and  that  no 
other  can  take  its  place.  How  does  the  pancreas  act  ?  Not  by 
simply  splitting  up  the  fat,  as  fat  broken  up  {e.  g.,  Lipanin  with  6 
per  cent,  fatty  acid)  was  not  absorbed ;  besides,  fat  was  voided  split 
up,  although  the  pancreas  was  removed.  Neither  is  the  fat  absorbed 
in  the  form  of  soap,  since  where  the  pancreas  secretion  enters  the 
bowel  the  reaction  is  acid,  and,  what  is  even  more  to  the  point,  soap 
