78 



FOODS AND FOOD ADULTERANTS. 

 TABLE No. 8. Analyses of butter sulstitute-s. 



1 40 butter fat, 15 oleo fat, 30 neutral lard. 

 2 Average 40 pounds per fat steer. 



ANALYTICAL RESULTS. 



The butters in table No. 6 were bought in open market and accepted 

 as genuine on the results of the analysis. Some of these, however, 

 ought justly to be classed in Table No. 7, as of doubtful purity. In 

 quite a number of cases the number of cubic centimeters, of decinormal 

 alkali required to neutralize the distillate from 2.5 groins of the fat 

 was less than 13. Nos. 1742, 1746, 1752, 1706, 1770, 1773, 1775, 1776, 

 1777, 1783, 1789, and 1792 come under this category. In all these 

 cases, however, except 1735 and 1768, the specific gravity is above 

 .910 at 40 C., and it would not be safe to condemn a butter as adulter- 

 ated which had that specific gravity, unless the microscope should re- 

 veal crystals of foreign fat. In these samples such was not the case. 



In the two cases mentioned, where the specific gravity fell below 

 .910, there are other reasons for thinking the samples pure. In 1765 

 the percentage of soluble acid, by Reichert's method, is high, viz, 5.02. 

 In 1768 it is still higher, viz, 5.21. With such proportions of soluble 

 acid it would not be possible to condemn the samples as adulterated 

 on the evidence of the specific gravity alone 



On the other hand, when the percentage of soluble acid is low, as in 

 1777, the specific gravity and saponification equivalent prevent the 

 classification of the sample among the doubtful butters. Neverthe- 

 less, should such a sample show with polarized light and a selenite plate 

 bi-refractive crystals, it would be a strong presumptive evidence of 

 adulteration. In any case, such a sample as 1777 would present nu- 

 merous difficulties to the analyst, especially if he were called to testify 

 in respect to its purity. 



In Table No. 7 similar difficulties are encountered. The specific gravi- 

 ties are uniformly low. On the other hand, the percentage of insoluble 

 acids are only suspiciously high in two instances, viz, 1748 and 1757. 

 In the first of these instances, however, the soluble acid is above the 

 limit of suspicion. The saturation equivalent is uniformly rather high, 



