Am.  Jour.  Pljarru. 
May,  1902. 
Emil  Scheffer. 
215 
sulph-hydric  acid,  concentration  by  the  aid  of  moderate  tempera- 
ture, etc. — involved  so  many  possibilities  of  change,  that  a  process 
of  isolation  and  purification  by  the  aid  of  less  energetic  agents  was 
a  desideratum.  He  remembered  that  his  old  professor,  Gmelin,  had 
pointed  out  during  his  lectures  the  facility  with  which  albumen  and 
allied  bodies  are  thrown  out  of  aqueous  solution  by  common  salt, 
and  I  remember  well  the  exultation  with  which  he  demonstrated  to 
me  the  fact  that  when  a  solution  of  pepsin  is  mixed  with  sufficient 
brine,  a  frothy  scum  gradually  develops  and  rises  to  the  surface, 
which  scum  on  closer  inspection  proves  to  be  composed  of  minute 
globules,  and  that  these  globules,  when  redissolved  in  water  by  the 
aid  of  a  little  hydrochloric  acid,  possess  the  digestive  qualities  of 
the  original  pepsin  solution  unimpaired.  It  remained  only  to  find 
suitable  methods  of  separating  the  pure  pepsin  and  to  reduce  it  to 
a  dry  condition  and  permanently  active  form.  As  is  now  well 
known,  this  is  a  very  simple  process,  but  it  was  not  so  simple  a 
matter  to  achieve  it  initially,  so  that  it  was  not  until  1872  that 
Scheffer  was  able  to  communicate  a  process  which  has  made  his 
name  famous  throughout  the  civilized  world.  Briefly  stated,  this 
process  consists  in  collecting  the  pepsin  globules  on  straining  cloths, 
expression  under  a  powerful  press,  washing  the  press-cake  with  a 
little  water  to  remove  salt  as  much  as  possible,  then  triturating  it  in 
a  mortar  with  milk-sugar  so  as  to  form  a  damp  powder,  which  is 
completely  dried  in  a  current  of  air  at  the  ordinary  temperature 
and  reduced  to  a  fine  powder.  This  is  finally  adjusted  by  the 
further  addition  of  milk-sugar  to  such  a  strength  that  a  stated 
quantity  will  effect  the  solution  of  a  stated  quantity  of  freshly 
coagulated  egg-white  in  a  definite  quantity  of  acidulated  water 
within  a  given  period  of  time. 
In  revealing  his  process  for  the  manufacture  of  "  saccharated 
pepsin  "  to  the  world,  Scheffer  has  undoubtedly  given  the  incentive 
to  the  more  intelligent  and  comprehensive  study  of  the  proteolytic 
ferments,  and  these,  in  their  turn,  have  encouraged  the  investigation 
and  study  of  biological  products  in  general.  It  is  unquestionable, 
that  with  the  advent  of  "  Scheffer's  pepsin  "  the  use  of  pepsin  in  the 
practice  of  medicine  secured  a  fast  and  permanent  foothold,  and  it 
need  not  be  told  that  hundreds  of  individuals  have  made  a  compe- 
tence by  the  manufacture  of  pepsin,  or  of  its  preparations — though 
none  have  been  so  generous,  as  was  Scheffer,  to  make  their  methods 
