852 



FOODS AND FOOD ADULTERANTS. 

 Free and combined acids of yellow wax. 



These results agreed with those of Hubl and Hehner, but the means obtained by the 

 French chemist are somewhat lower than those obtained by the other authors. They 

 found Borne few samples indicating a total acid content corresponding to 91 to 92 mil- 

 ligrams of potash for 1 gram of wax, although the lowest limit given by them is 92. 

 On the other side they did not find a quantity of fatty acids corresponding to a num- 

 ber above 94.7 milligrams of potash for 1 gram of wax. The greater part of the 

 samples examined by them contained a quantity of fatty acids corresponding to 92 to 

 95 potash forl gram of wax. The ratio of the two numbers representing the free and 

 combined acids was also found somewhat lower than that indicated by Hub). The 

 wax which is the least rich in fatty acids is always found to be that which is the 

 most colored, and in proportion as the color of the wax grows faint it is noticed that 

 the content of fatty acids increases. 



Estimation of non saturated acids of the oleic series. The method of Hubl for the ab- 

 sorption of iodine was applied for this determination. It must not be supposed, 

 however, that the acids of the oleic series present are the only compounds in wax which 

 are capable of absorbing iodine. The authors have shown that the hydrocarbons of wax 

 contain a certain number of bodies nonsaturated which are capable of fixing iodine. 

 However this may be, it must be allowed that by a treatment with iodine a new 

 number is obtained for beeswax, which is of considerable value for analytical pur- 

 poses. From 1 to 2 gram of wax are taken for each determination, and the method is 

 the same as that ordinarily used. The French yellow waxes are capable of absorbing 

 from 8.2 to 11 per cent of iodine ; that is to say, they contain from 9 to 12 per cent of 

 nonsaturated acids calculated as oleic acid. The difference in the amount of iodine 

 absorbed by the different samples examined did not exceed 3 per cent. 



Determination of the alcohols. The alcohols belong to the same series and possess 

 consequently the same chemical properties. The authors determined them en bloc by 

 submitting them to a reaction which is common to them and which is easily 

 measured. This is the important reaction of fatty alcohols described by Dumas and 

 Stas, viz, the reaction which they give when heated to a moderate temperature with 

 hydrate of potash. Under these conditions these alcohols are transformed into the 

 corresponding acids and at the same time they disengage hydrogen. The other 

 principles of wax, viz, the fatty acids, oleic acids, hydrocarbons, etc., are not changed 

 in the above operation, and by measuring the volume of hydrogen set free the pro- 

 portion of alcohol contained in the wax can be approximately determined. The 

 operation is carried on as follows : 



From 2 to 10 grams of the wax are melted in a porcelain capsule and mixed with 

 an equal weight of caustic potash finely pulverized. The mass is afterward treated 

 with three or four times its weight of potash, pulverized. The mixture is introduced 

 into a small flask or into a test tube, which is heated on a mercury bath to 250 for 

 two hours. The reaction begins at about 180, and after two hours of heating at 250 

 the evolution of hydrogen is completed. The gas is received in an apparatus invented 

 by M. Dupre. The evolution tube, fixed by a stopper in the neck of the flask, con- 

 ducts the gas to the upper part of the receiving flask, and another tube joined to this 

 conducts the gas to the inferior tubulure in the same way. These two tubes are each 

 furnished with a stopcock. The apparatus being thus disposed, and containing air 



