^FeJbTi872^RM*  \     New  Method  for  Preparing  Pepsin.  55 
of  hydrochloric  acid  to  the  fluidounce  of  water,  I  wished  to  determine 
whether  or  not  a  smaller  quantity  of  acid  would  answer  the  same 
purpose.  It  was  of  importance  to  ascertain  if  by  the  preparation 
of  liquid  pepsin  a  smaller  quantity  of  acid  would  produce  the  same 
results,  as  some  complaints  were  made  of  the  acidity  of  that  prepara- 
tion as  first  prepared. 
Of  four  experiments,  in  which  a  certain  quantity  of  pepsin  was  dis- 
solved in  1  ounce  of  water  with  respectively  4,  6,  8  and  10  drops  of 
hydrochloric  acid  of  1*17  spec,  grav.,  the  same  amount  of  coagulated 
albumen  was  dissolved  in  the  shortest  time  where  6  drops,  then  where  8 
drops  and,  thirdly,  where  10  drops  of  acid  were  employed,  while  the  ex- 
periment containing  4  drops  of  acid  had,  after  6  hours,  a  considerable 
quantity  of  albumen  not  dissolved.  I,  therefore,  made  all  my  sub- 
sequent experiments  with  a  solution  containing  6  drops  of  hydro- 
chloric acid  to  the  fluidounce  of  water,  at  a  temperature  of  100  to 
105°  F.,  and  each  vial  was  shaken  about  every  10  minutes. 
One  grain  of  purified  pepsin  in  4  oz.  of  acidulated  water  was  found 
to  dissolve  400  grs.  of  coagulated  albumen  in  18  hours  at  75°  F. 
One  grain  of  purified  pepsin  in  4  oz.  of  acidulated  water  dissolves 
500  grs.  coagulated  albumen  at  a  temperature  of  105°  F.,  in  6  hours. 
Ten  (10)  grains  of  saccharated  pepsin  dissolve  120  grs.  of  coagu- 
lated albumen  in  4  to  6  hours  at  100°  F. 
Although  I  did  not  succeed  to  prepare  a  pepsin  like  Wasman's,  of 
which  1  part  was  capable  of  dissolving  60,000  parts  of  coagulated 
albumen  I  found  that  the  digestive  power  of  pepsin  was  almost  inex- 
haustible. 
With  one-half  grain  of  purified  pepsin  in  2  oz.  of  acidulated  water 
I  dissolved  250  grains  of  coag.  alb.  ;  to  the  solution  was  added  an- 
other oz.  of  acidulated  water  and  250  grs.  of  albumen;  when  it  was 
again  dissolved  I  added  in  these  fractional  proportions  of  acidulated 
water  and  albumen,  until  finally  the  one-half  grain  had  dissolved 
1500  grains  of  coagulated  albumen.  That  it  would  have  dissolved 
still  more  I  proved  in  an  experiment,  mentioned  hereafter. 
Pebton  solution. — When  the  albumen,  which  by  the  digestive 
process  is  converted  into  albuminose  or  pepton,  is  perfectly  dissolved, 
the  resulting  pepton  solution  is  a  very  limpid,  thin,  slightly  yellowish- 
colored  liquid,  which,  when  filtered,  has  an  opalescent  appearance. 
By  addition  of  alcohol  it  remains  at  first  clear,  but  forms,  after  24 
hours,  a  gelatinous  precipitate. 
