292, REPoRT OF THE CHEMIST OF THE ~ 
(10) Large granules or chunks favor the retention and uneven 
distribution of buttermilk and we get mottles in the finished 
butter. 
(11) Salt brine, as it usually occurs in butter, has the power 
of hardening, condensing and. localizing in space the proteid 
(usually casein lactate) of butter. The action requires several 
hours. 
From these facts, it would appear that mottles in butter are 
due primarily, to the presence and uneven distribution of butter- 
milk adhering to the outer surface of the small granules; and, 
secondarily, to the effect of salt brine upon the proteid of the 
buttermilk thus retained in butter. In the absence of either salt 
or excess of buttermilk, we have no mottling. Mottling ocurs 
most frequently as the result of an uneven distribution of butter- 
milk in the presence of salt distributed either evenly or unevenly. 
Mottling may be produced by an uneven distribution of salt in 
the presence of an excess of buttermilk even when uniformly 
distributed. In general, those conditions that favor the elimina- 
tion of excess of buttermilk or its even distribution tend to pre- 
vent mottles; while those conditions that favor the retention and 
uneven distribution of buttermilk in butter tend to form mottles 
in the presence of salt. 
THEORETICAL CONSIDERATIONS RELATING TO THE FORMATION OF 
MOTTLES IN BUTTER, 
We have presented the facts showing that the formation of 
mottles in butter is due primarily to the presence and uneven 
distribution of an excess of buttermilk adhering to the outer 
surface of the small butter-granules, and, secondarily, to the 
action of salt brine upon the proteid of the buttermilk thus 
retained in butter. We desire to consider a little more fully how 
the action takes place. 
A mass of butter must be regarded as an aggregation of butter- 
granules more or less loosely compacted. There is a variable 
amount of space between the granules and in these interstices we 
find the salt brine and also the buttermilk that is left adhering to 
the outer surface of the granules. There exist, therefore, more 
or less extensive channels through which movement of brine or 
buttermilk may take place to a limited extent, when conditions 
