LARD AND LARD ADULTERATIONS. 453 



must be repeated, and only after a number of recrystallizations have 

 been made, and many slides taken with no appearance of beef fat crystals 

 can it be decided that no beef fat is present. I should say, as a result 

 of my own observations, that as small an admixture as 20 per cent, of 

 beef fat can readily be detected, but I should hesitate very much about 

 guarantying a detection of 10 per cent, or less, as the experts in the 

 Chicago case were confident of doing. 



The presence of a large amount of cotton seed oil facilitates, of course, 

 the detection of beef fat admixture by the microscope. That is, a com- 

 pound lard made up with say 10 per cent, of beef fat stearine, 50 per cent, 

 of lard, and 40 per cent, of cotton seed oil would be more likely to give 

 a characteristic beef fat crystallization than one made up with 10 per cent, 

 stearine, 65 per cent, lard, and 25 per cent, cotton seed oil, for the pro- 

 portion of lard to beef fat would be greater in the latter case and hence 

 more likely to predetermine a formation resembling the lard crystals. 

 Under the ordinary conditions of crystallization no crystals would likely 

 be obtained from the cotton seed oil. The crystallization shown in Fig. 

 18, Plate xxxvi, was obtained from a concentrated solution of cotton- 

 seed stearine in ether after it had stood at ordinary temperatures for 

 nearly a week. 



