Am.  Jour.  Pharm. 
Dec,  1921. 
|   Lactometer  and  Fat  in  Milk  Control. 
825 
TABLE  III. 
Lactometer  read- 
ing at  60°  F. 
%fat 
calculated  by 
formula  (16) 
26 
27 
28 
29 
30 
6.0 
5-o 
4.0 
3-o 
2.0 
When  by  the  aid  of  the  data  in  Table  III,  a  line  III,  is  laid 
off  on  the  same  axes  as  were  previously  used  (see  Fig.  1),  the  in- 
tersection of  line  III  with  line  II  shows  within  what  limits  Bialon's 
formula  is  suggested  for  use  in  the  method  herein  proposed.  Within 
these  limits,  any  calculated  value  of  F  is  the  least  or  minimum  fat 
percentage  in  a  mixed  mifk  that  is  above  suspicion  of  watering  and 
that  has  exhibited  the  corresponding  lactometer  reading.  As  an 
example,  consider  a  milk  found  to  have  a  lactometer  reading  of 
27.  The  minimum  per  cent,  of  fat  in  such  milk  if  it  is  above  sus- 
picion of  being  watered  is  5  per  cent.  Should  this  milk  by  actual 
analysis  be  found  to  contain  less  than  5  per  cent,  of  fat,  it  should 
be  set  aside  for  further  consideration. 
Considering  now  the  completed  graph  shown  in  Fig.  1,  the 
area  that  lies  above  the  broken  curve  formed  by  the  intersection  of 
lines  I,  II  and  III  contains  all  pairs  of  values  of  lactometer  and 
fat  to  be  found  in  the  mixed  milks  that  in  routine  work  may  be 
passed  by  the  analyst.  The  -  area  below  the  broken  curve  contains 
the  rest.  Hence  in  the  course  of  routine  milk  examinations  if  the 
values  found  for  L  and  F  be  located  by  the  analyst  on  Fig.  I,  it  be- 
comes a  simple  matter  to  set  those  milks  that  are  suspicious  apart 
from  those  that  may  be  passed. 
It  is  not  essential  that  a  Quevenne  lactometer  be  used  in  the 
work,  although  it  is  more  convenient.14  The  specific  gravity  can  be 
found  more  accurately  and  almost  as  quickly  with  a  Mohr-Westphal 
specific  gravity  balance.  The  result  thus  obtained  is  readily  converted 
into  Quevenne  degrees  by  formula  (4).  Since  L  =  1000  G  — •  1000, 
then,  for  example,  if  the  gravity  is  found  to  be  1.029  the  corres- 
"An  excellent  form  of  Quevenne  lactometer  is  that  recommended  by 
Shaw  &  Eckles,  1.  c.  footnote  5;  but  it  contains  no  thermometer.  The  com- 
mon form  in  use  is  an  improvement  made  by  Miiller  on  the  original  Quevenne 
lactodensimeter.    See  Miiller,  Priifung  der  Kuhmilch,  1877. 
