CHAP. IV.] THE CHOLESTERIN OF THE BILE, 339 



SECT. 12. THE CHOLESTERIN, FATS, SOAPS, LECITHIN AND REMAIN- 

 ING ORGANIC CONSTITUENTS OF THE NORMAL BILE. 



In addition to its specific constituents the salts of the bile acids 

 and the bile colouring matters and to the mucoid nucleo-albumin, 

 the bile contains in solution the following organic substances : 

 cholesterin : palmitin, stearin and olein : alkaline salts (i.e. soaps) of 

 palmitic, stearic and oleic acids : lecithin or its products of decom- 

 position : a trace of urea : a trace of a diastatic ferment. All these 

 bodies are described in other parts of this work, and the amounts in 

 which they occur in the bile, so far as they can be determined, will 

 be found in the tables exhibiting the results of the analyses of 

 the bile in Sect. 15 of the present chapter. It is only, therefore, 

 needful in this place to make a few remarks, chiefly with a view to 

 emphasizing the relative importance of certain of these constituents. 



The choies- An absolutely constant constituent is cholesterin, 

 term 1 ofbiie. w hi cn i s present in the bile of man in the proportion 

 of from 0*5 3 '5 per 1000. This constituent, which is insoluble 

 in water or aqueous saline solutions, is soluble in solutions of the 

 salts of the bile acids and of soaps and neutral fats, and it is in 

 virtue of these constituents that the bile is able to hold cho- 

 lesterin in solution. When we inquire whether the cholesterin 

 of the normal bile is formed in the liver or merely separated by 

 it we come to the conclusion that, almost certainly, the liver, in 

 reference to cholesterin, acts purely as an excretory organ. Cho- 

 lesterin is one of the principal constituents of the white matter 

 of the brain, of the spinal cord, and of medullated nerve fibres, 

 and it is a constituent of the blood corpuscles ; it appears most 

 likely that the function of the liver, in reference to it, is to separate 



>m the blood the excess of cholesterin which is set free in the 

 letabolic changes which have their seat in the nerve centres. 



This view rests upon theoretical considerations as well as upon certain 

 facts, a thorough control of which is, however, urgently needed at the 

 present time. It was for example asserted by Austin Flint, as a result 

 of apparently careful investigations, that the blood of the jugular vein 

 invariably contains much more cholesterin than that of the carotid artery. 

 Although Flint based upon his researches a hypothesis which has not 

 stood the test of further experiment, the facts above recorded have not 

 hitherto been disproved. Again Frerichs and Becquerel and Rodier assert 

 that in cases of jaundice, with complete obstruction to the flow of bile 

 into the intestine, the amount of cholesterin in the blood is remark- 

 ably increased. It must be admitted that it is in the highest degree 

 advisable that these particular determinations should be repeated, the 

 accurate methods of analysis which we now employ being substituted for 

 the cruder methods of the earlier enquirers. 



1 The description of Cholesterin will be found in VoL i. (1st edition), pp. 442 444. 



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