26 
Adicify  of  P(iHL-i'C<(tic  Kiffdds. 
f  Am.  Jour.  IMiariii. 
I      Jan.,  ItcV^. 
Quantify  of  pancreatic  Time  in  whii  li  tlio  ai  luuinic  lujint  was  reached, 
extract  employed.  Fumul.  Caloilated. 
\  0"02  cub.  cent.  o4  iniiuitc.'s.  o(i  ininute.s. 
I  (»-()4  18       "  18 
L        '  0-08        "                        f)       "  9  " 
I  (►•lO        "  7       "  7.'. 
i  8       "  S\  " 
0-4  4.i  ,-) 
II.      -I  0-2         "  10       "  10 
(O-Oo       "  40       "  40  " 
111  both  tliese  sets  of  observations  the  inverse  time  riite  comes  out 
with  a  very  near  approach  to  exactness.  WJien.  liowever,  only  a 
relatively  small  quantity  of  pancreatic  extract  was  employed,  the 
attainment  of  the  achromic  point  was  postponed  beyond  the  term  indi- 
cated by  the  rule.  Thus,  when  ()'004  cc.  of  the  extract  was  employed 
the  achromic  point  was  reached  in  125  minutes;  consequently,  with 
O'OOOo  cc.  extract  the  time  should,  according  to  the  rule,  have  been 
1,000  minutes,  but  it  was  actually  1,380. 
Influence  of  Temperature. — The  action  was  found  to  increase  in 
energy  (or  speed)  from  0°  to  30°,  tiience  to  45°  it  continued  steady; 
above  45°  it  became  less  and  less  energetic,  and  finally  ceased  between 
65°  and  70°. 
i  oniparatlve  Diastdsic  Values  of  (Ujferent  Pancreatic  Extracts. — The 
diastasic  value  of  an  extract  is  expressed,  in  the  author's  system,  by 
the  number  of  cubic  centimeters  of  standard  mucilage,  which  can  be 
brought  to  the  achromic  point  b}^  1  cc.  of  the  extract  to  be  tested  in 
five  minutes  at  a  given  temperature.  By  this  mode  of  estimating,  the 
author  found  that  the  extract  obtained  from  the  })ancreatic  tissue  of 
the  })ig  has  at  40°  a  meaii  diastasic  value  of  100,  those  of  the  ox  and 
sheep  at  the  same  tem[)erature  having  the  values  11  and  10  respect- 
ively. Filtered  human  saliva  has  a  diastasic  value  of  10  to  17  at  40°, 
and  its  energy  varies  with  the  temperature  in  exactly  the  same  man- 
ner as  that  of  ])ancreatic  extract  (  p.  1052).  ilia/^  ^//r^s'^^'^sc  has  a  dias- 
tasic value  of  4  to  5  at  40°,  increasing  to  10  at  abont  60°,  above 
which  it  diminishes,  but  does  not  cease  entirely  until  the  temperature 
is  raised  to  80°.  Several  specimens  of  human  urine  showed  a  dias- 
tasic value  of  0-03  to  0-13  at  40°. 
Proteolytic  Activity  of  Pancreatic  Extracts. —  Trypsiiiietry. — Milk 
digested  with  pancreatic  extract  accpiires  the  property  of  curdling  when 
boiled.  The  onset  of  this  reaction  occurs  earlier  or  later  according  to 
the  activity  of  the  extract,  and  the  quantity  of  it  employed ;  and  the 
time  of  its  advent  may  l)e  fixed  with  sufficient  accuracy  to  serve  as  the 
basis  of  the  method  of  measuring  the  proteolytic  activity  of  pancreatic 
