466 



Philippine Journal of Science 



1919 



Each of the six classes of oil A was divided into four parts, 

 of about 30 grams each, and stored March 24, 1917, under the 

 conditions given in Table II. 



Table II. — Conditions during storage. 



Designation. 



Sd 

 SI. 

 Od 

 01 



Conditions. 



Sealed, kept in the dark — 



Sealed, kept in the diffused light of the laboratory 



Open, in the dark 



Open, in the light - 



Rancidity fac- 

 tors. 



Light. 

 Air. 



Air and light. 



The sealed tubes contained practically no air space (about 

 0.5 cubic centimeter). The open samples were in 100 cubic 

 centimeter bottles closed only with a cotton plug; in these the 

 oil formed a layer 2 centimeters deep. The temperature during 

 storage was about 30° C. 



Another sample of oil, B, was prepared in the same manner 

 as oil A, but was found to have only 0.1 per cent acidity. This 

 was divided into six parts as described in Table I. These were 

 stored on April 19, 1917, exposed to air and light, under the 

 same conditions as series 01 of oil A and will, therefore, be 

 designated as series OIB. 



On April 11, 1919, the thirty samples were transferred to 

 glass-stoppered bottles and their examination for rancidity was 

 begun. During the time required for the various determina- 

 tions, which were made in duplicate, the samples were kept 

 as much as possible in a refrigerator to prevent further change. 

 The results of the examination are given in Table III, in which 

 the first twenty-four samples are from oil A, and the remaining 

 six from oil B. 



EXPLANATION OF TABLE III 



Rancidity factors. — The abbreviations a, 1, s, i, m, n, are 

 used to designate air, light, fat-soluble enzymes, fat-insoluble 

 enzymes (together with possible microorganisms), moisture, 

 and nonfatty material, respectively. 



Acidity. — The first column gives the determinations made 

 by Parker before storing the oil. Evidently sterilization caused 

 a rise from 0.37 to 0.52 in the case of oil A. 



Iodine number. — The Hanus method was used. Duplicates 

 differed by about 0.04. No data on the original iodine numbers 

 were available, but they may be taken as being close to those 

 of the sealed samples, since the latter had no opportunity of 



