ELIMINATION OF CHOLESTERINE BY THE LIVER. 455 



cholesterine. It will be remembered that there was a large quantity of this substance 

 in the internal jugular, and but a small quantity in the carotid, showing that it was 

 formed in the brain. We now give the conclusion of these observations, which bears 

 upon the separation of cholesterine from the blood : 



Experiment I. Specimens of blood were taken from the hepatic artery, portal vein, 

 and hepatic vein, and a small quantity of bile was taken from the gall-bladder. These 

 specimens were treated in the manner already indicated ; viz., evaporated and pulverized, 

 extracted with ether, the ether evaporated and the residue extracted with boiling alco- 

 hol, this evaporated, a solution of caustic potash added, and the specimen then subjected 

 to microscopical examination. 



Microscopical examination of the extract from the portal vein showed quite a number 

 of crystals of cholesterine. These were observed after the fluid had nearly evaporated. 



Microscopical examination of the extract from the hepatic artery, made after the fluid 

 had nearly evaporated, showed a considerable quantity of cholesterine, more than was 

 observed in the preceding specimen. There were also observed a few crystals of ster- 

 corine. 



The first examination of the extract from the hepatic vein, which was made just 

 before the potash was added, showed a number of fatty masses, with some crystals of 

 stercorine. The solution of potash was then added, and, two days after, another careful 

 examination was made, revealing nothing but fatty globules and granules. The watch- 

 glass was then set aside and was examined eleven days after, when the fluid had entirely 

 evaporated. At this examination, a few crystals of cholesterine were observed for the 

 first time. There were also a number of crystals of margaric and stearic acid. 



All the examinations of the extract from the bile showed cholesterine; and the pre- 

 cipitate consisted, indeed, of this substance in a nearly pure state. 



Taking these experiments in connection with the first observations upon the carotid and 

 internal jugular, while the one series demonstrates pretty conclusively that cholesterine 

 is formed in the brain, the other shows that it disappears, in a measure, from the blood 

 in its passage through the liver, and is passed into the bile. In other words, it is formed 

 in the nervous tissue and is prevented from accumulating in the blood by its excretion 

 by the liver. This suggests an interesting series of inquiries ; and this fact, fully sub- 

 stantiated, would be as important to the pathologist as to the physiologist. But, in order 

 to settle this question, it is necessary to do something more than make an approximative 

 estimate of the quantity of cholesterine removed from the blood by the liver. The quan- 

 tity thus removed in the passage of the blood through this organ should be estimated, if 

 possible, as closely as the quantity which the blood gains in its passage through the brain. 

 This estimate, however, is more difficult. The operation for obtaining the specimens of 

 blood, in the first place, is much more serious than that for collecting blood from the carot- 

 id and internal jugular. It is very difficult to take the unmixed blood from the hepatic 

 vein ; and the exposure of the liver, if prolonged, may interfere with its eliminative func- 

 tion, in the same way that exposure of the kidneys arrests, in a few moments, the flow 

 from the ureters. It is probable, however, that the administration of ether does not 

 interfere with the elimination of cholesterine by the liver, as it does, apparently, with its 

 formation in the brain. Anesthetics, as we know, have a peculiar and special action upon 

 the brain, but they do not appear to interfere with the functions of vegetative life, such 

 as secretion or excretion ; and, we may suppose, they would not interfere with the depu- 

 rative function of the liver. It is fortunate that this is the case, for the operation of 

 taking blood from the abdominal vessels is immensely increased in difficulty by the strug- 

 gles of an animal that is not under the influence of an anaesthetic. 



With the view of settling the question of the disappearance of a portion of the choles- 

 terine of the blood in its passage through the liver, by an accurate quantitative analysis, 

 we repeated the operation for drawing blood from the vessels which go into and emerge 

 from the liver. In the first trial, the blood was drawn so unsatisfactorily, and the oper- 



