338 PROCEEDINGS OF SECTION B. 
We have now as our constants 7:27 for the oatmeal and 1:02 
for the wheatmeal. 
In the light of the determinations herein mentioned, these 
figures, I think, are justified, subject, of course, to any modification 
that future and more extended investigation may render necessary. 
Having established the presence of the adulterant, by micro- 
scopical recognition of the starch granules, it remains to make an 
estimation of the fat a given sample contains, in order to arrive at 
the degree of adulteration. The following is the formula for the 
calculation :— 
Percentage of wheatmeal = 100— 
Oat constant—percentage of fat in Be) 
( Oat constant—wheat constant. 
I have found this process give good results when applied to 
mixtures containing known quantities of each meal. For example : 
A mixture of equal parts of oat and wheatmeal gave 4:2 per cent. 
of fat then 
4°20 
7 oO” 
i 
6°25 
) = 49-1 per cent. of wheatmeal. 
Another sample prepared by mixing together 70 parts of oat- 
meal and 30 parts of wheatmeal yielded 5:32 per cent. of fat, 
equalling 31 per cent. of wheatmeal. Both these results tend to 
confirm the process, being very close to the actual truth. 
I have not considered the question of the sophistication of oat- 
meal with grain other than wheat, because this latter is the only 
adulterant generally used in Sydney.* However, it is fortunate 
that the fat content of any grain that might lend itself to the 
purpose, is low.7 
In this investigation the fat was extracted in each case from 5 
grammes of the meal by petroleum ether, acting in the Soxhlet 
apparatus, with ample condenser, for from two to three hours. 
Schleicher and Schull’s patent thimbles were used to contain the 
meal, which was dried in the air-bath immediately before extrac- 
tion. The petroleum ether was also water frec. The fat was 
caught in a small wide-mouthed flask, and after the disposal of the 
ether, was dried at 100° C. in the air-bath, until constant in weight. 
* In England the chief adulterant of oatmeal is said to be barley meal. 
+ Barley, for instance, according to Blyth, contains 1°7 per cent. of fat. 
