Churnability  of  Cream. 
117 
from  different  cows  of  the  same  breed.  In  order  to  test  this 
factor,  six  samples  of  milk  from  six  different  Shorthorn  cows 
were  taken,  as  also  four  samples  from  individual  Guernsey 
animals,  all  of  which  were  in  the  Showyard  at  Liverpool. 
Each  sample  of  milk  was  analysed  chemically,  and,  in 
order  to  see  if  any  law  governing  the  variations  could  be 
discovered,  the  following  ratios  were  worked  out  : — 
Fat  : Lactose. 
Lactose  : Proteid. 
Proteid  : Fat. 
The  average  of  each  class  was  taken,  and  the  amount  of 
variation  from  this  average  in  each  case.  It  was  found  that 
the  variations  were  large,  and  indifferently  positive  and 
negative.  In  short,  no  regularity  in  variation  could  be  found, 
and  it  is  obvious  that  experiments  must  be  made  with  a larger 
number  of  milks  than  six,  if  any  useful  conclusion  is  to  be 
drawn. 
Taking  the  results  of  microscopical  examination,  the  sizes 
and  numbers  of  the  fat  globules  in  each  individual  sample 
of  milk  were  plotted  as  curves.  The  same  was  done,  also,  for 
the  mixed  samples  of  milk,  and  it  was  hoped,  by  this  method, 
that  the  milks  could  be  classified  according  to  the  size  of  the 
globules.  In  some  cases,  it  did  appear  as  though  they  could 
be  classified  in  this  manner,  as  is  shown  by  the  samples  of 
milks  given  below  in  extenso ; both  being  from  individual 
Shorthorn  cows,  however. 
Milk  A. 
Milk  B. 
Percentage 
Percentage 
Size  of  globule 
of  total  fat 
Size  of  globule 
of  total  fat 
present 
present 
2 microns  . 
8'9 
2 microns . 
2-75 
3 
28-7 
3 „ 
6'45 
4 „ . . . 
33  (5 
4 „ 
11-75 
5 
153 
5 „ 
12-60 
9-1 
6 „ 
22-80 
7 „ 
22-40 
8 „ 
17-60 
956 
96-35 
Contrasting  these  two  milks,  it  is  obvious  that  the  first  is  of 
more  uniform  nature  as  regards  the  size  of  the  globules  than 
the  second  ; in  the  first  sample,  a range  of  from  two  to  six 
microns  in  the  size  of  globules  covers  nearly  9fi  per  cent,  of 
them,  while  in  the  second,  a range  of  from  two  to  eight  microns 
is  required  to  cover  practically  the  same  percentage. 
