520 FOODS AND FOOD ADULTERANTS. 



CHICAGO, June 1, 1883. 



This certifies that I have analyzed t\vo .samples of lard, marked respectively No. 1 

 aud No. 2, received from Mr. Mixer cm May 30, 1833. and find that both are adulterated 

 with heef stearine or its equivalent amount of tallow to the extent of at least 20 per 

 cent. 



G. A. MAKINER. 

 Per HOSKINS. 



One of his methods was by taking equal proportions of alcohol and ether, and into 

 that mixture putting a certain amount of pure lard, and also an equal weight of the 

 samples to he tested. Tbe lards were warmed, and were then poured into the vessels 

 containing the mixture under exactly the same conditions. After some time more or 

 less of the steariue separated. In pure lard, treated in the way he has described, the 

 separated substance, which is chiefly steariue, rarely exceeds 1 per cent. One of the 

 samples given him by Mr. Mixer gave less than 4 per cent. ; one gave over 5 per cent. 

 Another process, known as Blythe's pattern process, is to take a piece of glass, ehem 

 ically cleaned, and having a thin film of water on it. On this is dropped a drop of 

 the melted substance. In the case of lard one pattern is produced, in the case of tal- 

 low a different pattern, and in the case of tho mixture of the two a still different and 

 intermediate pattern is produced. He regards this as an absolute test and one easily 

 applied. Another test used is to ascertain the difference in time taken in saponifying 

 samples. Tallow takes much less time to saponify than lard does, under proper and 

 tho same conditions. This process gives quite accurate results. These are the chief 

 tests he depended upon in his chemical examinations of the samples now in question. 

 The processes he has described are recognized by authorities, and have all been pub- 

 lished as authority. He has during the past two winters had considerable experience 

 in examinations as to the adulteration of butter, and has studied the subject of fats 

 to a considerable extent. He considers the results of his examination of the samples 

 given him by Mr. Mixer as conclusive in respect to their quality ; there is no possibil- 

 ity ofa doubt as to the correctness of his conclusions in respect to them. In regard 

 to the presence of foreign oil in lard there is an absolute test, known as the elaidino 

 test. It especially applies to drying oils. Nitrous oxide is made by heating mercury 

 with nitric acid. In treating non-drying oils with it the point noted is the fat which 

 is solid. It, makes no such combination with drying oils, aud when they are in large 

 quantity they separate and come to the top and can be seen as liquid. In other cases 

 they form more or less of a semi-solid ; he thinks almost anybody could see the differ- 

 ence when pointed out, although it requires considerable experience in the use of the 

 microscope to bo able to detect these differences unaided. All his examinations were 

 carried on parallel with examinations of samples of pure lard rendered by himself, at 

 least a part of which was leaf lard. H; thinks there may be a lit! le difference between 

 the proportions of etearine in leaf lard and fat taken from tho sides of the hog. It is, 

 however, but slight. After all his examinations of the samples in question in this case,' 

 it is his absolute conclusion that the lard is adulterated to the extent of 20 per cent, of 

 foreign material. He calculates tho percentage of adulteration from the basis that, :\n 

 pure lard never contains more than 1 per cent, of pure steuriue, aud that tallow con- 

 tains about 9 per cent., therefore, as these samples contained none less than 4 per cent., 

 there mnst have been added to tho lard beef tallow, or some of its derivatives, sulli- 

 cient to account for tho 3 per cent, of excess, and as three nines are twenty-seven, he 

 concludes there was over 20 per cent, of adulteration in the samples. The test of 

 adulteration is by the amount of pure stearine found in the sample. 



KXACT MKTHOP OF ANALYSIS. * 



A portion of tho fat was warmed and mixed with about ten times its weight of a 

 mixture of equal parts of absolute alcohol and ether. After allowing it to stand 

 about twenty-four hours the residue was tillered and weighed. 



'Op. cit., p. 1-19. 



