23,6 Perkins and Cruz: Oils in Chaulmoogra Group 553 



rotation and freezing point of fatty acids. Sample G is typical 

 of the commonly found rancid commercial chaulmoogra oil which 

 is dark brown when melted but has a large amount of light 

 semisolid deposit even at 30° C. Many physicians and patients 

 accustomed to this product, obtained from partly rotten seeds, 

 look with suspicion on the more carefully prepared oils. Sam- 

 ples H, J, and L were obtained from P. K. Sen, Chittagong, In- 

 dia. We were informed from reliable sources at the time that 

 only selected Taraktogenos kurzii seeds were used by this manu- 

 facturer, and that the oil was cold pressed. These oils were of 

 much better quality than the crude oils above mentioned, hav- 

 ing less color, acidity, and odor and practically no sediment at 

 30° C. The most carefully manufactured oils which we were 

 able to obtain were D, E, and J, from Shiongi & Co., Osaka, 

 Japan. These samples were very light in color, clear, and al- 

 most odorless, but it is difficult to decide from the data whether 

 they are Taraktogenos kurzii or Hydnocarpus wightiana. 



Specific gravity. — The determination of specific gravity was 

 made with a hydrometer at 30° C. Different samples of the 

 oil from the same species show expected variations on account 

 of varied acidity, difference in treatment, etc. The oils of the 

 chaulmoogra group all show a high specific gravity (0.943 to 

 0.956), matched by only a few other oils. 



Due to its variation in different samples of the same oil, the 

 specific gravity is of no value in determining the species of an 

 unknown oil, but a specific gravity below 0.940 in an alleged 

 chaulmoogra or hydnocarpus oil would indicate adulteration. 

 Refractive index. — An Abbe refractometer was used, either 

 at 30° C. or within one or two degrees of this temperature. In 

 the latter case a correction of 0.00038 per degree was applied. 

 The chaulmoogra group shows a high refractive index, but 

 not sufficiently high to be distinctive, and there seems to be no 

 significant variation within the group. 



Freezing point. — This simple though rather inexact determina- 

 tion was made to obtain a relative idea of the tendency to solid- 

 ity exhibited by the various oils. The sample was cooled in a 

 test tube and the temperature at which it became semisolid was 

 noted. (See also freezing point of fatty acids.) 



Rotation. — The optical rotation was determined in a quartz 

 wedge saccharimeter, using white light filtered through di- 

 chromate. Usually the sample was placed in a 4-centimeter tube. 

 All results are expressed in angular degrees per decimeter, as 

 is customary for optically active liquids. To compare these 



