22 Milk and Its Products 
and even onions, without danger of contamination of 
the milk. The presence of wild garlic and wild 
onions in pastures is a source of bad flavor in the 
milk in a considerable portion of the country. Where 
this is the case it is, of course, more difficult to 
overcome the bad fiavor; but by allowing the cows 
to pasture for a comparatively short time only im- 
mediately after’ milking, and keeping them up and 
giving them some dry food for three or four hours 
before milking, there will be a great deal less an- 
noyance from this source. 
The non-volatile fats——The non-volatile fats make 
up about 85 per cent of the whole amount of fat, 
and consist of a more or less uncertain and variable 
mixture of several fats, of which olein and palmitin 
make up the chief part. They are glycerides of the 
corresponding fatty acids—oleic, palmitic, stearic, myr- 
istic, ete., and differ from one another chiefly in 
their hardness or melting point. Olein is liquid at 
ordinary temperatures; palmitin and the others are 
solid. Olein melts at about 41° F., the hard fats at 
various temperatures from 130° to 150° F. The 
mixture of the whole, as we find them in ordinary 
butter, melts at from 92° to 96°F. The hardness 
or softness of different butters, depending largely 
upon varying proportions of olein. Considerable doubt 
exists as to the relative proportions of the various 
fats and fatty acids. Browne* gives the following 
percentages of volatile and non-volatile fatty acids: 
*Jour. Am. Chem. Soe. 21, 822. 
