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in behavior between a filtered and an unfiltered oil is most pronounced 
during the first few months. On longer standing, the acid values tend 
to approach each other. 
The most important fact brought out by this work is that by far the 
greatest deterioration which an oil undergoes takes place in the copra 
itself. After an oil has been expressed from the dried meat, its change 
on standing is very slight compared with that which is found in the 
same time while it is in the copra. For instance, sample No. 1 was 
prepared from anhydrous copra, which had stood in a closed jar during 
about seven months (under much better conditions than copra is ordi- 
narily kept) ; its free acid was 1.2 per cent; an oil expressed from this 
copra when it was fresh had only 0.77 per cent of free acid after it 
had stood for seven months in tin; this same copra after remaining three 
weeks over water and one week more in the air yielded an oil containing 
23.3 per cent free oleic acid. Samples Nos. 19 and 20 were prepared 
from copra which, when fresh, gave an oil with almost no free acid. 
Fresh coconut meat on standing for even a short time in the air becomes 
covered with mold and produces an oil of a more or less rancid character 
(cf. No. 14). No great amount of rancidity was developed in any case 
until signs of mold or bacterial growth were visible on the surface of the’ 
copra. From this it would seem very probable that the splitting up of 
fat and the accompanying “rancidity” produced in copra are in a large 
measure due to the action of micro-organisms, which have an excellent 
culture medium in the sugar, albuminoids, and water which exist, 
together with the oil, in coconut meat. 
Koenig, Spiechermann, and Bremer,® in their valuable paper on the 
decomposition of fats by micro-organisms, have conclusively shown 
that cottonseed meal containing a sufficient amount of water, is attacked 
by molds and bacteria, and that the oil therein is, on long standing, 
almost completely destroyed. In the accompanying experiments the 
methods used by these authors were followed, with certain modifications, 
which consisted chiefly in substituting freshly prepared anhydrous copra 
for cottonseed meal, and in paying especial attention to the amount of 
free acid developed. 
The copra used for this work was prepared by grinding up fresh 
coconut meat and drying it at 90° to 100° GC. under a partial vacuum, 
until the meat was anhydrous. It was then kept over sulphuric acid, 
to be used as needed. This product had become quite brown during the 
prolonged drying, but yielded an almost colorless oil, of a sweet taste, 
and which contained about 0.15 per cent free acid as oleic. 
Ten-gram samples were weighed out in large, stoppered test tubes and 
each tube was inoculated with one drop of a solution made from some 
° Koenig, Spiechermann, und Bremer: Beitriige zur Zersetzung der Futter- und 
Nahrungsmittel durch Kleinwesen, I. Die Fettverzehrenden Kleinwesen. Ztschr. 
f. untersuch, d. Nahrungs-u. Genussmittel (1901), 4, 721, 769. 
