592 
Milk. 
f  Am.  Jour.  Pharm. 
\       Nov.,  1884. 
of  water,  and  to  a  much  greater  extent  by  the  presence  of  the  diastase 
to  which  the  author  has  previously  given  the  name  casea.se.  In  one 
case  the  porportion  of  soluble  casein  was  061  per  cent.,  but  under  the 
influence  of  casease  it  increased  in  8  hours  to  1*80,  and  in  24  hours 
to  2*20  per  cent. /after  which  it  remained  constant,  one-third  of  the 
total  casein  being  still  in  the  colloidal  condition.  The  destruction  of 
the  equilibrium  thus  established  required  a  very  much  longer  time,  or 
the  addition  of  a  further  quantity  of  casease.  The  casein  can  be  more 
quickly  converted  into  the  soluble  form  by  addition  of  some  of  those 
microbes  which  produce  casease  (loc.  cit.),  and  which  continually  secrete 
this  substance,  whilst  at  the  same  time  they  use  up  the  casein  already 
existing  in  the  soluble  form  for  their  own  nourishment.  The  secretion 
of  the  casease  is  in  fact  the  means  by  which  these  microbes  prepare 
their  own  food  at  the  expense  of  the  suspended  and  colloidal  casein 
and  is  strictly  analogous  to  the  action  of  the  pancreatic  juice  in  the 
higher  animals. 
Hammarsten  supposed  that  the  action  of  rennet  on  milk  is  to  split 
up  the  casein  into  two  new  albuminoids,  one  of  which  is  insoluble  in 
presence  of  the  calcium  phosphate  contained  in  the  milk,  and  carries 
down  a  portion  of  this  phosphate  with  it,  whilst  the  other,  correspond- 
ing to  lacto-protein,  and  called  whey-protein  by  Hammarsten,  remains 
in  solution.  The  author  treated  milk  with  rennet  free  from  casease, 
care  being  taken  to  prevent  the  access  of  bacteria  as  far  as  possible, 
and  examined  the  resulting  liquid  by  the  filtration  method.  The 
result  of  one  out  of  a  number  of  experiments  are  given  in  the  follow- 
ing table : 
In  suspension. 
In  solution 
Milk. 
Whey. 
Milk. 
Whey. 
0.85 
5-37 
5'73 
0-46 
0-37 
0.36 
  0-23 
0-17 
0.17 
0-40 
0-43 
8-06 
1-31 
6-31 
6-69 
The  proportion  of  soluble  casein  and  of  dissolved  calcium  phosphate 
is  the  same  in  both  the  milk  and  the  whey.  The  suspended  calcium 
phosphate  is  however,  carried  down  together  with  the  fat  and  the 
casein  in  the  curd.  Hammarsten?s  supposition  is,  therefore,  not  con- 
firmed by  experiment,  since  the  amount  of  soluble  casein  is  not 
