8i8 
Lactometer  and  Fat  in  Milk  Control.  \Am^onr-^arm- 
(      Dec,  1921. 
later  detailed  work  because  these  are  the  values  determined  at  the 
outset  in  routine  milk  work. 
In  States  that,  like  Pennsylvania,  have  expressed  in  the  stat- 
utes 1  minimum  legal  percentages  of  fat  and  total  solids,  and  that 
do  not  provide  additional  penalties  for  skimming  and  watering,2 
the  analyst  does  well  to  confine  his  evidence  to  data  showing  the 
milk  in  question  to  be  sub-standard.  It  is  worth  while  in  such  States 
to  establish  that  a  suspected  milk  is  skimmed  or  watered  only  in 
those  cases  where  the  percentages  of  fat  and  of  total  solids  are 
above  the  legal  minima.  The  method  suggested  in  this  paper  em- 
bodies this  idea. 
In  normal  mixed  milks  the  constituents  are  present  in  fairly 
constant  proportions.  The  relations  between  various  constituents 
have  found  expression  in  numerous  milk  formulas  3  some  of  which 
1  Milk  and  Cream  Act,  approved  June  8,  191 1,  forbids  the  sale  of  "milk 
which  contains  less  than  three  and  one-quarter  (zVa)  per  centum  of  butter- 
fat,  and  less  than  twelve  (12)  per  centum  of  milk  solids,"  etc. 
2  In  the  State  of  Massachusetts,  the  penalty  for  the  sale  of  milk  which  is 
adulterated  is  more  severe  than  for  the  sale  of  milk  below  the  legal  standard." 
Lythgoe,  Jour.  Ind.  Eng.  Chem.,  VI,  p.  900,  1914.  See  also,  Joum.  Off.  Agr. 
Chemists,  August,  1921. 
3  These  may  be  found  in  various  text-books  Among  the  more  valuable 
of  the  recent  formulae  are  those  due  to  Lythgoe  (footnote  2)  resting  upon  the 
total  solids,  the  sugar,  the  fat  and  the  ash,  which  may  be  used  in  distinguishing 
