FATS LECITHIN CHOLESTEROL. 1 17 



time, is that the formula C27H 44 0, or C27H 46 O, may be assigned to it and 

 that the molecule contains a double bond and also an alcohol hydroxyl. 

 Recent investigations * have shown that cholesterol belongs to a group of 

 chemical compounds widely distributed in the vegetable kingdom, but not 

 hitherto found in the animal economy. Cholesterol is evidently a terpene. 

 The animal organism, therefore, contains hydro-aromatic compounds. 



At present, cholesterol is considered to occupy an isolated position in 

 the animal kingdom. In the vegetable world we could easily understand 

 its formation from the terpenes in a number of ways. From its consti- 

 tution, it hardly seems possible that cholesterol originates in the animal 

 organism. Animal cholesterol is undoubtedly vegetable cholesterol which 

 has been utilized by the animal organism for its requirements. We know 

 absolutely nothing about its decomposition in the animal body. Bond- 

 zynski and Humnickni 2 have isolated a substance similiar to cholesterol 

 from human faeces, which does not possess a double bond, but has two atoms 

 of hydrogen more than cholesterol. About one gram of this compound is 

 excreted daily. It has been called " dihydro-cholesterol," or coprosterol. 

 The reduction is undoubtedly brought about by the activity of putre- 

 factive bacteria. 



We know practically nothing of the significance of cholesterol in the 

 animal organism. Its general occurrence leads us to conclude that it is of 

 great importance in cell metabolism. We cannot possibly consider it as 

 a decomposition product. We only know of one definite property of 

 cholesterol. This relates to the hemolytic action of lecithin and cobra 

 poison. We have seen that lecithin accelerates the activity of cobra 

 poison. Conversely, cholesterol retards the action of lecithin. We have 

 seen that if we add snake venom to blood corpuscles, suspended in water 

 and freed from serum, no hemolysis results; when, however, a trace of 

 lecithin is added, hemolysis quickly follows. If we then add a minute 

 quantity of cholesterol suspended in methyl alcohol, the lecithin, which 

 previously had caused the cobra poison to become active, is now without 

 effect. The blood corpuscles are not dissolved. Lecithin and cholesterol 

 occur in all cells, and especially in the blood corpuscles. It is probable 

 that they also show their antagonism towards one another in these. We 

 are acquainted with various kinds of blood, whose corpuscles are dissolved 

 by cobra poison alone; others require the presence of lecithin. It is 

 perfectly possible, and even probable, that lecithin is present in these 

 different kinds of blood corpuscles in different states of combination, 



1 A. Windaus: Ber. 36, 3752 (1903); 37, 2027 (1904); 37, 3699 (1904); 37, 4753 

 (1904). O. Diels and E. Abderhalden: ibid. 36, 3177 (1903); 37, 3092 (1904). Cf. also G. 

 Stein: Inaug. Diss. Freiburg, 1905. 



2 St. Bondzynski and V. Humnicki: Z. physiol. Chem. 22, 396 (1896-97); Ber. 29, 

 476 (1896). Miiller: Z. physiol. Chem. 29, 129 (1900). 



