406 USES OF THE LIVER DUCTLESS GLANDS. 



The constant and invariable presence of cholesterine in the bile assimi- 

 lates it in every regard to the excretions, of which the urine may be taken as 

 the type. Cholesterine always exists in the blood and in certain of the tissues 

 of the body. It is not produced in the substance of the liver, but is merely 

 separated from the blood by this organ. It is constantly passed into the 

 intestine, and is discharged, although in a modified form, in the fasces. 

 Physiologists know of no office which it has to perform in the economy, any 

 more than urea or any other of the excrementitious constituents of the urine. 

 It accumulates in the blood in certain cases of organic disease of the liver 

 and gives rise to symptoms of blood-poisoning. 



Origin of Cholesterine. Cholesterine exists in largest quantity in the sub- 

 stance of the brain and nerves. It is also found in the substance of the liver 

 -probably in the bile contained in this organ the crystalline lens and the 

 spleen ; but with these exceptions, it is found only in the nervous tissue and 

 blood. It is either deposited in the nervous matter from the blood or it 

 formed in the brain and taken up by the blood. This is a question, however 

 which can be settled experimentally. 



In a series of experiments made in 18G2, it was invariably found that tl 

 proportion of cholesterine in the blood of the rnternal jugular vein and the 

 femoral vein was greater than in the arterial blood. In experiments 

 on dogs not etherized, the blood of the jugular vein contained, in one in- 

 stance 23'3 and in another 59'8 per cent, more cholesterine than the arterisi 

 blood of the same animals. The blood of the femoral vein contained about 

 6'3 per cent, more cholesterine than arterial blood. In three cases of hemi- 

 plegia, cholesterine was found in normal quantity in blood taken from the 

 arm of the sound side, while blood from the paralyzed side contained uc 

 cholesterine (Flint). 



These observations point to the production of cholesterine in the tissues : 

 and the fact of its existence, under normal conditions, in the nervous tissue 

 renders it probable that the chief seat of its production is the substance of 

 the nerve-centres and nerves. The question of its formation in the spleen is 

 one that has not been investigated. 



In another series of experiments, it was shown that the blood lost che 

 lesterine in passing through the liver. In one observation it was found tin 

 the arterial blood lost a little more than 23 per cent, and the portal bk 

 about 44 per cent., in passing through the liver (Flint). 



The portal blood, as it goes into the liver, contains but a small percent 

 age of cholesterine over the blood of the hepatic vein, while the percental 

 in the arterial blood is large. The arterial blood is the mixed blood of the 

 entire system ; and as it probably passes through no organ which diminishe 

 its cholesterine before it goes to the liver, it contains a quantity of this sul 

 stance which must be removed. The portal blood, coming from a limit 

 part of the system, contains less cholesterine, although it gives up a certaii 

 quantity. In the circulation in the liver, the portal system largely predomi- 

 nates arid is necessary to other important actions of this organ, such as the 

 production of glycogen ; but soon after the portal vein enters the liver, it 



