10 
ince some considerable difficulty was encountered in deter- 
mining the iodine value, the figure is not taken as final. Ap- 
parently the absorption is accompanied by the formation of some 
unstable compound, which is decomposed by sodium thio- 
sulphate. From these constants, it appears that the fat consists 
chiefly of the glyceryl esters of fatty acids, the larger portion of 
which are saturated, but no attempt has been made to determine 
the composition of the fat. 
On exposing the fat to the atmosphere, a change in colour and 
in form was noticed. The fat gradually lost its green colour and 
assumed a pale yellow shade; a marked tendency for films to 
agglomerate was noticed, and finally it became granular in 
ducted with a view to determining the cause of the changes. 
The following tables will show the course of the experiments : — 
A.—3'9536 grammes, exposed to air and light. 
Time of exposure Gain per gramme 
i Actual gain. per day. 
1 iy 00024 gm. ree 000061 gm. 
= 0-0070 ,, aay POUT? 
2 
Oe es 00216 ,, se 0-00546 
4 i 00312 ,, cn UUOGS 
5 vee 00504 ,, oe 0°00425 __,, 
These figures are no measure of complete change, since, owin 
to agglomeration, the lower layers were not sufficiently exposed. 
B.—35913 grammes, exposed to air, without access of light. 
Time of exposure Gain per gramme 
in days. Actual gain. per day. 
1 See 0-0003 gm. ... 0°0000835 gm. 
2 or O-O011 ,, ee 0:0003063 
3 0:0025 __,, eat 00006961 __,, 
4, 00074 ,, ae 0:002060 5 
4 0:0082 _,, ae 0:000761 ; 
b 
In this experiment, there was no agglomeration, and the only, 
change in form was the appearance of small white points in the 
green exposed surface. 
C.—3-9894 grammes, exposed to light in nitrogen. 
For a period extending over seven days no change in weight 
took place. 
excluded from light the change was extremely small, and only 
affected the most exposed portions. The effect that this oxidation 
has upon the solubility of the fat in the ordinary solvents was 
next ascertained. The data are tabulated below, and will again 
