.516 FOODS AND FOOD ADULTERANTS. 



of mercury, in which case the nitric acid should be somewhat diluted. 

 The red vapors produced by the action of iron on nitric acid may also 

 be conducted directly into the oil. 



One part of the strong nitric acid may also be shaken with three to 

 five parts of the oil and a solutiom of nitrite of potash added drop by 

 drop with constant shaking. 



Attempts have been made to measure the relative hardness of the 

 elaidine produced by the distance which a plunger carrying a known 

 weight would sink into it, and the data thus obtained have been used 

 for quantitative calculations. 



SPECTROSCOPIC EXAMINATION. 



The absorption spectrum of an oil depends upon the character of the 

 coloring matter contained therein. Many vegetable oils give a spectrum 

 characteristic of chlorophyll. 



Cotton oil gives a banded absorption spectrum. 



The use of the spectroscope in examinations for lard adulteration is 

 probably not as extensive and general as the merits of the process 

 would warrant. 



FURTHER QUALITATIVE REACTIONS. 



There are other qualitative reactions which might sometimes prove of 

 value in the examination of lard and its adulterations. 



These are the methods of Chateau, Faure, Heydenreich, Peuot, Grace 

 Calvert, Fltickiger, and Glaessner. 



A full description of these methods is given by Benedikt.* 



ABSTRACTS OF METHODS OF LARD ANALYSES, WITH EESULTS THEREOF. 



! Employed in the case of McGeoeh, Everingham & Co. vs. Fowler Bros., before Chicago Board of 



Trade. ] 



Much progress has been made in the science of lard analysis since 

 the famous case of McGeoeh, Everiugham & Co. vs. Fowler Bros., the 

 notes of which have been published in pamphlet form by Knight & 

 Leonard, Chicago, 1883. 



The complaint against the Fowler Bros, rested on the charge that 

 they had sold prime steam lard which contained other than hog fat. 

 The complaint was brought before the Chicago Board of Trade, and was 

 heard by the board of directors thereof. Samples of the suspected lard 

 were submitted to a large number of chemists, and an abstract of their 

 methods of analyses and the results obtained follows : 



TESTIMONY OF DR. P. B. ROSE.t 



He can generally tell, when a sample of prime steam lard is sent to him, if there 

 have been any impurities pnt into it, by examining its color and quality; the sarn- 

 1>1<>H are sent to him for the purpose of seeing whether tin- lard is up to the proper 



Analyse d<>r Fette und Wachsartrn. n. I'.H. itaeq. 

 ' Pamphlet mentioned, i>. 11(5. 



