FATS AND RELATED SUBSTANCES. 59 



the harder residue is sometimes called lard stearin. It has 

 about the consistence of butter. By subjecting beef suet to 

 the same treatment a soft portion known as olco oil is sepa- 

 rated from a solid residue called beef stearin. The oleo oil 

 is the material most often employed under the name of oleo- 

 margarin as a substitute for butter. A mixture of somewhat 

 similar consistence is made in other ways; for example by 

 combining cottonseed oil with beef stearin. 



OLEOMARGARIX is the name given by law to these butter 

 substitutes in the United States. Sometimes the fats are 

 churned with milk or mixed with a certain amount of real 

 butter to furnish a product with flavor suggesting butter. 

 The name butterine is usually given to such mixtures and 

 when properly made they are wholesome and in every way 

 as good as butter from the standpoint of nutritive value. 



BUTTER. The fat of milk is a very complex mixture and 

 an exact separation has not yet been made by the methods of 

 chemical analysis. According to the older notion butter fat 

 contains essentially olein, stearin and palmitin, with a little 

 butyrin, to which the flavor and odor are largely due, but it 

 has been shown that other glycerol esters are certainly present. 

 The results of some recent examinations may be approximately 

 expressed as follows : 



Glyceryl butyrate ..................................... 7.0 



Glyceryl caproate, caprylate and caprate ................ 2.0 



Glyceryl oleate ....................................... 36.0 



Glyceryl myristate, palmitate and stearate ............... 55.0 



100.0 



From various investigations it appears that these fats are 

 not present as simple esters, but may possibly exist in combi- 

 nations represented by formulas like this: 







C 3 H 6 C 16 H 31 O 2 



CH T 2 



The melting point of butter fat is between 38 and 45 

 On melting 100 parts by weight of pure butter fat, saponifying, 



