454 IOWA ACADEiMY OF SCIENCE Vol. XXV, 1918 



first two instances tlie variation is so slight that, allo^vinor for 

 even the smallesit error, the line of difference is indistinct. It 

 is then the color tests that mark the dividing line beween the 

 almond, peach, and apricot oils. The zinc chloride test is the 

 one employed, as follows: Add five drops of the strong zinc 

 chloride solution to ten drops of the oil. If there is no change in 

 color after stirring, the oil is identical with that from the almond 

 nut. If the color changes to purple or brownish purple, the oil 

 is like that from the peach kernel. If the mixture changes to a 

 muddy or a dirty brown, the oil is tlie same as that from the 

 apricot kernel. In the sample of oil being examined, there was 

 no change in color, showing that the oil in this analysis is the same 

 as that from the almond nuts. 



The taste aud odor of cyanogen in the freshly cracked cherry 

 pits is evidence of the presence of nitrogen. By the use of the 

 Gnunning method we determined the percentage of nitrogen in 

 the kernels and found it to be no less than 5.6. It is to be ex- 

 pected that the ether extraction would remove a part of the 

 cyanogen with the oil. We took a gram of the dried residue 

 after all the oil had been extracted and made another nitrogen 

 determination. In this w^e found 4.2 per cent of nitrogen, show- 

 ing that the main portion of the nitrogen was neither extracted 

 by the ether nor expelled by the long heating on the water bath. 



The residue from the crushed ■cherry pits was taken from the 

 flask and dried in the air for ten hours. Then it was heated on 

 the water bath at 100° C. for fifteen hours to expel the remaining 

 ether and the moisture. The dry residue was weighed and the 

 loss in weight found to be 20.9 grams. The oils extracted 

 weighed 18.8 grams, leaving a difference of 2.1 grams. This is 

 no doubt the weight of the water expelled from the residue when 

 it was heated to drive off the remaining ether. 



When cherry seeds or oil bearing nuts are ground up with 

 cold water the amygdalin breaks up in an emulsion. The oil is 

 partly broken down in the process and glucose sugars constitute 

 one of the resulting products. To confirm the presence of the 

 glucose sugars in the water extraction, we treated a quantity 

 of the dried seeds with water for twenty-four hours. We titrated 

 a fractional part with standard Fehling solution and found 13.8 

 per cent of sugar present. Reaction: 



CjoH.yNO, i+2H,0=C7H80+HCN+2CeH: jOe 



