288 EXCRETION. 



ering 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 precipitate consisted, indeed, of this 

 substance in a nearly pure state. 



Taking these experiments in connection with the first 

 observations on 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 inter- 

 esting series of inquiries ; and this fact, fully substantiated, 

 would be as important to the pathologist as to the physiolo- 

 gist. 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 quantity thus removed in the passage of 

 the blood through this organ should be estimated, if pos- 

 sible, as closely as the quantity which the blood gains in its 

 passage through the brain. But this estimate is more diffi- 

 cult. The operation for obtaining the specimens of blood, 

 in the first place, is much more serious than that for collect- 

 ing blood from the carotid 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 function, 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 choles- 

 terine by the liver, as it does, apparently, with its formation 



