AFebrXvTi9aor2m*}         Animal  Digestive  Ferments.  57 
"  ozmazome  " — names  given  then  to  other  forms  of  proteids.  He 
attempted  to  ascertain  its  nature,  whether  simple  or  complex; 
noted  the  curdling  action  on  the  casein  of  milk  and  proved  that  this 
was  not  due  to  the  acid  ;  likewise  studied  its  proteolytic  power  on 
muscular  tissue  and  fibrin.  Further  showed  that  it  was  not  mucin 
or  a  constituent  of  mucus,  but  secreted  by  the  glands  of  the  mucous 
membrane.  He  did  not  isolate  the  pure  ferment  (it  has  not  been 
accomplished  yet),  but  developed  a  method  of  purification  by  precipi- 
tation with  mercury  chloride  and  lead  acetate,  the  metal  being 
subsequently  precipitated  by  hydrogen  sulphide  and  removed  by 
filtration.  He  was  the  first  to  ascribe  a  ferment  nature  to  the  active 
principle  of  the  gastric  juice,  to  which  he  gave  the  name  pepsin. 
In  1839  Wasmann — a  pupil  of  Miiller  and  Schwann — following 
the  method  of  the  latter,  prepared  a  dry  amorphous  product  by  pre- 
cipitating the  filtrate,  after  removal  of  the  metal,  with  alcohol,  and 
drying  the  precipitate  at  low  temperature. 
Wasmann  obtained  a  very  potent  product  in  this  way  from  the 
pig  stomach,  extracting-  with  water  at  35-400  C. 
He  is  stated  by  French  as  having  considered  the  active  principle 
a  combination  of  pepsin  and  hydrochloric  acid. 
The  younger  Burdach  published,  in  1841,  the  results  of  various 
experiments  tending  to  show  that  acidulated  infusions  of  many 
organs  and  tissues  possess  proteolytic  powers.  A  glance  at  his- 
results  shows  that  this  power  was  exceedingly  weak. 
In  1842,  Blondlot  in  France,  Bassow  in  Russia,  succeeded  in 
establishing  gastric  fistulae  in  dogs ;  later  on  extended  to  the  pan- 
creas by  Bernard,  Heidenhain,  etc.  Blondlot  in  his  treatise  speaks 
of  the  nature  of  chyme,  and  in  a  rambling,  incoherent  manner  of 
various  fermentations,  etc. 
Lehmann,  in  1842,  treats  of  the  manner  of  the  proteolytic  action 
of  pepsin,  considers  it  a  protein  of  cellular  origin  and  capable  of 
transforming  ingested  albuminoids  into  substances  susceptible  of 
absorption.  He  credits  Wasmann  with  regarding  the  granular 
matter  in  the  glandular  cells — the  "  cystoblastima  "  of  Schwann — 
as  either  pepsin  itself  or  the  substance  from  which  pepsin  is  formed. 
In  1845  Bouchardat  and  Sandras  published  results  obtained  with 
the  pancreatic  juice  of  fowls,  exhibiting  great  diastasic  power.  They 
subsequently  continued  their  investigations  on  rabbits. 
These  authors  are  given  credit  for  being  the  first  to  discover  the 
