HAWORTH. | Origin of Oil and Gas. 198¢ 
ORIGIN OF THE OPTICALLY ACTIVE CONSTITUENTS. 
“The contributions of the decomposition products of albuminous mat- 
ters, as well as the remains of resins, balsams, terpenes, tannins, etc., to 
the optical activity of petroleum are only of minor importance. This 
activity is rather due to the presence of a single substance, because the 
fractions of petroleum which show the maximum optical activity, from 
whatever fields they are derived, boil at about the same temperatures. In 
almost all oils the content of optically active substances begins to appear 
in the fractions between 200° and 250°, and above this reaches a va- 
riable maximum value and then falls rapidly. In the case of oil from 
Pechelbron, the speaker, together with Lederer, has recognized two max- 
ima, one of +0.5° at 69° to 76.5° under 17 mm. pressure, and another 
of 6.6° at 281° to 291° under 13 mm. pressure. Between these two points 
several fractions were inactive. If the same oil is distilled under ordi- 
nary atmospheric pressure there is a marked change in optical activity, 
due to compensation or racemization. The two maxima remain, only the 
inactive portions are shifted to lower fractions. Still more surprising 
is the fact noted by tk. speaker and Bartnitzki that petroleum from Java 
is leavo-rotatory in its lower fractions (—4.8° below 190°), higher up it 
is inactive, and still higher it becomes dextro-rotatory. These observa- 
tions are most easily explained on the supposition of Marcusson that 
cholesterin is the substratum which causes the optical activity of pe- 
troleum. 
“The speaker supported this hypothesis by the following results and 
considerations: The optical maxima of petroleum from different sources 
appeared, generally, in fractions of the same boiling-point which is the 
same as that found in the products obtained from cholesterin. The 
speaker, together with Hullard, found that cholesterin gives products of 
different boiling-points depending upon the manner of distillation. In 
vacuum it distills undecomposed and remains leavo-rotatory. When dis- 
tilled rapidly at ordinary pressure, the product may be either dextro- or 
leavo-rotatory. After distillation is carried on for an hour a noticeable 
inversion of the rotation from left to right occurs at from 300° to 350°. 
When cholesterin is distilled by itself under pressure or with fish-oil, 
according to Marcusson, dextro-rotatory products are obtained. If this 
distillation under pressure is repeated the activity decreases or disap- 
pears at the corresponding temperature, even without distillation. In 
lke manner phytosterin distills in vacuum unchanged and without loss 
of leavo-rotatory power. When not too rapidly distilled under atmos- 
pheric pressure strongly dextro-rotatory distillates are obtained. (Twenty 
grams cholesterin distilled three times gave products of +112° and 
+128° rotation.) Water was constantly obtained as a decomposition 
product. It is by no means necessary to assume that the highly active 
distillates of cholesterin contain a product free from oxygen. An ether 
of cholesterin might be present. R. Albrecht found in Galician petroleum 
of +25° rotation 0.8 per cent. oxygen. Since a petroleum so strongly 
active as that of Galicia contains only one per cent. of the most highly 
active fraction, it follows that small quantities of the substratum, choles- 
