278 REPORT OF THE CHEMIST OF THE 
The curd of different butters and of the same butters at differ- 
ent ages presents quite different appearances. For special ex- 
amination of its properties, the curd of butter.is obtained by 
dissolving the fat in ether, or by melting the butter at as low a 
temperature as practicable and allowing the curd and brine to 
settle beneath the layer of butter-fat. The curd prepared from 
fresh butter, made from cream having an acidity of .5 or .6 per 
ct., is gelantinous in appearance and does not readily separate 
into small particles on standing. The curd of butter that is a 
few weeks old often appears granular. This is due, as we shall 
point out later, to the action of salt upon the physical properties 
of the casein lactate. | | 
THE RELATIONS OF PROTEIDS OF BUTTER TO THE 
MOTTLING OF BUTTER. 
The subject of mottled butter has attracted more or less atten- 
tion and has been much discussed in dairy papers. However, 
the literature relating to actual investigations of mottled butter 
is very meagre. The only available work done in this country is 
described in Bulletin No. 64, Maryland Agricultral Experiment 
Station, by C. F. Doane, on “A Study of the Cause of Mottled 
Butter’; and in Bulletin No. 80 of the Iowa Agricultural Ex- 
periment Station, by G. L. McKay and C. Larsen, there is a brief 
treatment of ‘ Gritty Salt as a Cause of Mottles.” In order to 
ascertain the consensus of dairy authorities on this subject, the 
following inquiries were sent to the most prominent teachers of 
dairying in our county: | 
1. Does mottling of butter occur at one particular time of year 
more than another? If so, when? Why? 
2. What different kinds of mottling do you recognize? 
3. What do you regard as the causes that produce mottling? 
4. Has ripening of cream anything to do with mottling? If 
so, how? 
. Does the temperature of churning influence mottling? 
. Does the temperature of the wash-water influence mottling? 
. Does the size of granules influence mottling? ; 
8. Does salt influence mottling? 
9. Has the butter color used anything to do with mottling? 
“Is Ot 
