LARD AND LARD ADULTERATIONS. 421 



The characteristics mentioned above are emphasized when the melt- 

 ing point of the fat acids is considered. These numbers seem much 

 higher than would be expected. 



B. CHEMICAL PROPERTIES. 



(a) Volatile acids. The statements made in regard to the volatile 

 acids in a pure lard are also applicable to cotton-seed oil. 



For 5 grammes of cotton oil the quantity of deci-normal alkali con- 

 sumed is slightly greater than for pure lard and may amount to as much 

 as .5 cc. 



If cocoa oil is present the number will be much higher. 5 grammes of 

 pure cocoa oil will consume from .7 to .8 cc of the deci-normal alkali. 



(b) Saponification equivalent. In the samples reported the mean 

 saponificatiou equivalent was 283.8, although in some instances quite, a 

 difference was noticed from this figure. 



(c) Iodine number. Cotton oil possesses in a much higher degree 

 than lard the property of absorbing iodine. This is due not only to the 

 large percentage of oleic acid which it contains, but also probably to 

 the presence of a small amount of liuoleic acid or some homologue 

 thereof. In the samples examined in no case did the iodine number fall 

 below 100 and in one instance it rose to 11G.97. The mean iodine num- 

 ber was 109.02. 



(d) Reaction with nitrate of silver. A more important property even 

 than its power of absorbing iodine is shown by cotton oil in the reduc- 

 tion of silver to the metallic state under certain conditions. The test 

 may be applied, as already indicated, either to the oil itself or to the 

 fatty acids thereof. The silver is either reduced in the form of a metal- 

 lic mirror deposited on the sides of the vessel or in minute black parti- 

 cles which give a brown or black appearance to the liquid. In some 

 cases the liquid shows a greenish tint. 



OTHER PROPERTIES. 



The refined cotton oil used in adulterating lard has a pleasant taste, 

 is almost odorless, and possesses a faint yellow color. Its resemblance 

 to olive oil is so marked that for all culinary purposes it forms an ex- 

 cellent substitute therefor. Cotton oil possesses slight drying qualities 

 which render it unfit for lubricating delicate machinery. Therefore it 

 can never take the place of sweet oil for that purpose. 



STEARINES. 







The steariues used in the adulteration of lard arc derived chiefly from 

 lard, certain parts of beef fat, and cotton oil. These are generally called 

 lard stearine, oleo stearine, and cotton-oil steariue, respectively. 



