504 FOODS AND FOOD ADULTERANTS. 



licultural Society of the Alpes Maritime**. Mr. 13rull6 began upon the 

 known principle that vegetable oils, when oxidized by the application 

 of certain acids, assume different shades of color, lie then hit upon 

 the use of albumen to fix and accentuate these delicate gradations of 

 tint. The report of the commission has recently been published, and 

 gives the process of Mr. Brulle such complete and unqualified indorse- 

 ment, both for its simplicity and the exactness of its results, that the 

 subject assumes a practical importance not only to the countries which 

 produce olive oils, but to those which, like our own, import them as 

 costly luxuries for general consumption. In its series of experiments 

 at Nice the commission first applied the process of Mr. Brulle to six 

 classes of samples, viz, first, to pure olive oil, then to the same oil with 

 an added admixture of 5, 10, 20, and 50 per cent., respectively, of cotton- 

 seed oil, and finally to the pure cottonseed oil itself. When the result 

 had been established", by repeated experiments with each grade of sam- 

 ples a fac-simile of the tint produced by each successive degree of adul- 

 teration was prepared by dissolving certain pigments in stated quanti- 

 ties of water. Thus the process and a standard system of proofs were 

 put within reach of any person having a good eye for color and a slight 

 familiarity with chemical manipulations. 



THE NEW PROCESS. 



The process of Mr. Brulle is as follows : Put into a test-tube ] A grains* 

 of pure albumen (this should be gently heated in the flame of an alcohol 

 lamp to expel any remaining moisture in the albumen which might 

 otherwise modify the exactness of the result), then add 3 cubic centi- 

 meters of nitric acid and 10 cubic centimeters of the oil to be tested (tho 

 quantity of each ingredient used is, of course, immaterial, provided the 

 above relative proportions are maintained ; a test-tube graduated me- 

 trically is the most convenient for the purpose) ; the mouth of the tube 

 is then closed with a cork to prevent the boiling over of the liquid dur- 

 ing ebullition, but pierced with a small orifice to permit the escape of 

 vapor, which would otherwise explode the tube. The materials are 

 mixed by shaking, but the nitric acid quickly settles to the bottom. 

 Now warm gently in the lamp the part of the tube containing the oil, 

 then apply the flame to the underlying stratum of acid. A fierce ebul. 

 lition soon ensues, and when this is at its height plunge the tube into 

 ice water sufficiently cold to chill the contents to 4 C, or its equiva- 

 lent 40 F. During the cooling process there is developed an oleagin- 

 ous precipitate, ranging in color from-pale yellow to reddish brown, 

 according to the proportion of cotton oil contained in the tested sample. 

 The experiment requires only tho simple apparatus above mentioned, 

 and occupies only four or five minutes. 



The findings of the commission at Nice are tabulated in its oflicial 



' r.o ing. 



