5§4 
Substitute  Infant-Feeding, 
/Am.  Jour.  Pharm. 
1  December,  1900. 
ing  4  per  cent,  and  over;  (3)  Ayrshires,  Holsteins  and  common 
stock,  known  as  "  milk  cows,"  giving  milk  containing  3  per  cent, 
and  a  little  over. 
A  physician  in  a  given  neighborhood  should  find  out  what  breeds 
of  cattle  supply  the  milk  to  the  vicinity,  in  order  to  know  about  the 
proportion  of  butter  fat  contained  in  the  milk.  The  milk  of  one 
dairyman  will  run  quite  uniform  from  day  to  day,  as  the  variations 
in  the  milk  of  individual  cows  will  compensate  each  other. 
In  mother's  milk  the  fat  is  usually  between  3  and  5  per  cent.,  or 
nearly  three  times  the  proteids,  which  vary  from  1  to  2  per  cent.; 
while  the  sugar  is  between  6  and  7  per  cent.  As  noted  above,  cows' 
milk  will  contain  from  3  to  5  per  cent,  butter  fat,  while  the  proteids 
about  average  4  per  cent.,  and  the  sugar  from  4  to  5  per  cent.  It 
is  pretty  well  settled  that  in  mixed  cows'  milk  the  proteids  about 
equal  the  fat  when  the  fat  does  not  exceed  4-5  per  cent.  When  the 
fat  in  the  whole  milk  is  above  4-5  per  cent.,  the  proteids  are  a  little 
less  than  the  fat. 
While  in  most  cases  a  medium  grade  of  milk  will  be  supplied, 
especially  in  towns  and  cities,  still,  we  must  be  prepared  to  properly 
modify  either  very  rich  or  poor  milk.  An  easy  way  of  calculating 
percentages  is  to  take  advantage  of  the  process  known  in  the  dairy 
industry  as  the  "  deep  setting  process  of  creaming."  This  consists 
in  putting  milk  into  tall,  narrow  vessels  and  cooling  to  about  400  F. 
After  twelve  to  twenty-four  hours  practically  all  the  fat  of  the  milk 
will  be  found  in  the  creamy  layer,  the  remaining  milk  often  contain- 
ing no  more  than  -2  to  -5  per  cent.  Milk  that  has  been  bottled  and 
kept  cool  for  twelve  to  twenty-four  hours  is  subjected  to  the  condi- 
tions necessary  for  successful  "  deep  setting  "  creaming,  and  usually 
contains  a  layer  of  cream  in  the  neck  of  a  quart  bottle,  between 
three  and  four  inches  deep,  measuring  from  the  top,  or  about  six 
fluidounces.  The  line  separating  the  cream  from  the  remaining 
milk  is  distinct.  Unless  the  creamy  layer  is  distinct  when  the  milk 
is  delivered,  it  is  probable  that  bottling  has  not  been  done  at  the 
dairy,  but  in  the  town  or  place  of  delivery.  Not  only  is  the  proper 
creaming  thus  interfered  with,  but  the  chances  of  contamination  are 
increased. 
By  taking  all  of  the  cream  and  part  of  the  remaining  milk  from 
the  quart  bottle  of  milk  and  mixing  in  certain  proportions,  top 
milks, rich  or  poor  in  fat, can  be  had  that  maybe  utilized  in  feeding 
