Full resolution (JPEG) - On this page / på denna sida - VII. The Liver - Bile Concretions
<< prev. page << föreg. sida << >> nästa sida >> next page >>
Below is the raw OCR text
from the above scanned image.
Do you see an error? Proofread the page now!
Här nedan syns maskintolkade texten från faksimilbilden ovan.
Ser du något fel? Korrekturläs sidan nu!
This page has never been proofread. / Denna sida har aldrig korrekturlästs.
446 THE LIVER.
two methyl groups, and which also contains an isopropyl group.
It is also generally admitted that cholesterin contains only one double
bond, which occurs in a vinyl group, CH:CH2, at the end. No constitu-
tional formula for cholesterin can be given; still there is no doubt but
that it is a complex terpene which stands in close relation to retene as
well as to the cholic acids.
By the reduction of cholesterin by metallic sodium and amyl alcohol, Diels
and Abderhalden as well as Neuberg and Rauchwerger obtained a dihydro-
cholesterin, the a-cholestanol, C2 7H48 0. On treating cholestenon, the ketone of
cholesterin, Diels and Abderhalden obtained a second dihydrocholesterin,
the @<holesta?wl, which Willstatter and E. W. Mayer obtained directly from
cholesterin in ethereal solution by reduction with hydrogen and platinum-black.
According to Diels and Linn * /3-cholestanol is obtained from cholestenon by
the action of sodium and amyl alcohol, and a-cholestanol with sodium amylate.
The relation of these bodies to each other is still not understood. These dihydro-
cholesterins have a physiological interest in regard to the question whether they
are identical or not with koprosterin, which will be discussed below.
On heating cholesterin, when contaminated with iron, to 300-320°, according
to Diels and Linn, 2
it in part yields cholestenon and partly an isomeric cholesterin,
the fl-cholesterin. This last body can be retransformed into cholesterin by the
saponification of the cholesteryl benzoate.
Cholesterin occurs in small amounts in nearly all animal fluids and
juices. It occurs only rarely in the urine, and then in very small quanti-
ties. It is also found in the different tissues and organs, especially
abundant in the brain and the nervous system; further, in the yolk of
the egg, in semen, in wool-fat (together with isocholesterin), and in
sebum. It also appears in the contents of the intestine, in excrements,
and in the meconium. It especially occurs pathologically in gall-stones
as well as in atheromatous cysts, in pus, in tuberculous masses, old
transudates, cystic fluids, sputum, and tumors. It does not exist free
in all cases; for example, it exists in part as fatty-acid esters in wool-
fat, blood, lymph, brain, vernix caseosa and epidermis formations. Sev-
eral kinds of cholesterin, called phytosterines, have been found in the
vegetable kingdom.
Cholesterin which has been crystallized from warm alcohol on cooling,
and also that which is present in old transudates, contains one molecule
of water of crystallization, and melts at 148.5° C. when dried in a vacuum,
and forms colorless, transparent plates whose sides and angles frequently
appear broken, and whose acute angle is often 76° 30’ or 87° 30’. In
large quantities it appears as a mass of white plates which shine like
mother-of-pearl and have a greasy touch.
Cholesterin is insoluble in water, dilute acids, and alkalies. It is
neither dissolved nor changed by boiline; caustic alkali. It is easily
1
Willstatter and Mayer, Ber d. d. chem. Gesellsch., 41; Diels and Linn, ibid., 41.
2
Ibid., 41.
<< prev. page << föreg. sida << >> nästa sida >> next page >>
