ITS FORMATION. 97 



on in the liver, and hence a part of the iron conveyed by the 

 portal vein is carried off through the liver into the intestinal 

 canal. Moreover, I was unable to find any iron in the serum of 

 the blood of the portal vein, when free from red blood-cells. 



Of the remaining organic constituents of the bile, the choles- 

 terin is that which has received the most attention. It occurs, as 

 we have already seen, in normal blood (see vol. i. p. 278) ; and it 

 is contained in that of the portal vein, although, in consequence 

 of the preponderance of true fat, it can only be recognised and 

 measured by the microscope with much difficulty. But indepen- 

 dently of this, the frequent occurrence of cholesterin in morbid 

 products (namely, in serous, encysted exudations, as, for instance, 

 hydrocele) without any simultaneous affection of the liver, or 

 without the simultaneous occurrence of other biliary constituents 

 in the collective juices, sufficiently indicates that this substance is 

 a product of the general metamorphosis of tissue, and that the 

 liver is merely the organ by which, in the normal condition, this 

 lipoid is separated. 



We have already seen why the occurrence of gall-stones rich 

 in cholesterin, will not warrant the conclusion that there is an 

 increased formation of this substance. The separation of choles- 

 terin from the bile depends only on mechanical causes, and is 

 independent of quantitative relations. Were we inclined to 

 assume that there was a cholesterin-diathesis, we should at all 

 events be astonished to observe, that when we found an exudation 

 consisting almost entirely of a pulpy mass of pure crystals of 

 cholesterin, gall-stones were never, or very rarely, simultaneously 

 present. 



It is unnecessary to offer any remarks regarding the origin of 

 the fats and the fatty acids of the bile, since we have so often 

 referred to the abundance with which fat occurs both in the blood 

 of the portal vein and in the hepatic cells ; the saponification of 

 the free fats proceeds also in other places ; as, however, the fatty 

 matters of the bile are for the most part saponified, while it is 

 chiefly unsaponified fats which are found in the fat-cells, it would 

 seem as if the fatty acids of the bile were first formed in the 

 hepatic cells. 



This circumstance appears to us to be opposed to the de- 

 hiscence of the hepatic cells assumed by certain authors ; for even 

 in fatty liver, or in certain physiological conditions in which the 

 hepatic cells are filled with fat-globules, we neither find that the 

 bile contains a large amount of unsaponified fat or any augmenta- 



VOL. II. H 



