55 
Dairy  Cattle  and  the  Butter  Test. 
Conclusion. 
One  of  the  first  questions  which  arises  in  connection  with 
the  churnability  of  milk  is  that  of  its  physical  character.  The 
consideration  of  milk  as  an  emulsion,  in  the  strict  sense  of 
the  term  is  by  no  means  universally  accepted.  The  presence 
or  absence  of  an  albuminous  or  mucoid  enveloping  film  round 
each  fat-corpuscle  is  not  yet  satisfactorily  determined.  In 
either  case  the  point  need  not  be  considered,  inasmuch  as 
Fig.  10.— Kerry.  Milk  x 500  diam. 
the  condition,  whatever  it  may  be,  is  the  same  in  all  the 
different  breeds  and  therefore  is  not  responsible  for  the 
observed  differences  in  the  relative  churnabilities  of  milks. 
Another  question  for  investigation  is  the  influence  of  the 
variable  proportions  of  the  chemical  constituents  of  the  milk 
serum.  The  emulsifying  powers  of  casein,  and,  in  a lesser 
degree,  lactose,  are  well  established  facts  ; and,  in  view  of 
