476 
The  Salts  of  Milk 
f  Am.  Jour,  Pharm. 
\      Sept..  1889. 
it  becomes  more  consistent  after  cooling,  and  this  change  is  accentuated 
each  time  the  operation  is  repeated  up  to  a  certain  point.  (4).  50 
grams  dissolved  in  450  cc.  of  85  per  cent,  alcohol  produces  on  shaking 
a  glistening  precipitate,  whilst  pure  oleic  acid  dissolves  completely; 
other  oils  give  deposits,  but  not  of  the  same  character.  The  precipi- 
tate is  collected,  washed  with  alcohol,  dried,  and  is  then  found  to  melt 
fit  about  47°.  It  is  easily  saponified,  yielding  a  soda  soap  completely 
soluble  in  water,  with  which  it  forms  a  jelly  on  cooling  when  only 
present  to  the  amount  of  1  :  100.  (5).  If  Poutet's  reagent  be 
applied  to  the  impure  acid,  the  mass  remains  more  or  less  liquid, 
whilst  oleic  acid  becomes  solid  by  the  following  day.  (6).  A  thin 
film  of  the  impure  acid  soon  becomes  resin-like,  whilst  the  oleic  re- 
mains almost  unchanged.  (7).  If  a  few  drops  of  impure  acid  are 
added  to  soda-lye,  an  intense  yellow  color  is  produced,  whilst  the 
pure  acid  gives  a  grayish  tint  only. 
THE  SALTS  OF  MILK  AND  THEIR  RELATION  TO  THE 
BEHAVIOR  OF  CASEIN.1 
By  F.  Soldnee. 
Two  series  of  determinations  of  the  ash  constituents  of  milk  gave 
the  following  results  in  grams  per  litre  of  milk : — 
CI.  P205.         K20.         Na20.  CaO.  MgO. 
I.. .0.820  2-437  1-885  0*465  1*720  0'205 
II..  .0-980  2-400  1-720  0510  1*980  0*200 
The  sulphuric  acid  was  not  determined,  as  it  does  not  pre-exist  in 
the  milk,  but  is  produced  from  the  sulphur  of  the  albuminoids  •  the 
small  amount  of  iron  was  also  neglected.  In  grouping  the  ash  con- 
stituents as  salts,  account  has  to  be  taken  of  the  fact  that  a  portion  of 
the  phosphoric  acid  found  in  the  ash  is  derived  from  the  phosphorus 
of  the  casein ;  the  amount  of  phosphoric  acid  to  be  deducted  is  0*581 
gram  per  litre  of  milk,  assuming  the  latter  to  contain  3  per  cent,  of 
casein. 
Hammarsten  showed  that  casein  has  acid  properties,  yielding  salts 
with  bases,  and  obtained  a  calcium- derivative  which  contained  0*8  to 
1*2  per  cent,  of  lime.  The  author  finds  that  there  are  two  distinct 
compounds  with  calcium ;  the  one,  containing  2*39  per  cent,  of  lime, 
shows  an  alkaline  reaction  with  litmus,  but  not  with  phenol phthalein  ; 
1Landw.  Versuchs  Stat,  xxxv,  351—436  ;  from  Jour.  Chern.  Soc,  June,  1889. 
