278 LIPOIDS. 



Physiological Relations. 



Occurrence. Small quantities occur in most of the animal 

 fluids. It was originally discovered by Gren in biliary calculi, 

 and has since been recognised as a constant ingredient of the 

 bile. In the normal condition cholesterin is dissolved in the bile, 

 and hence cannot be recognised under the microscope : even in 

 the bile removed from the dead body we rarely find tablets of 

 cholesterin (Gorup-Besanez*) and in these cases we cannot tell 

 whether it depends on an augmentation of the cholesterin or 

 on its separation in consequence of the decomposition of tauro- 

 cholic acid. Frerichsf found no cholesterin in several examina- 

 tions which he made of the bile in cases of fatty liver. 



Cholesterin was first distinctly recognised as a normal con- 

 stituent of the blood by Lecanu, Denis, Boudet, and Marchand ; 

 while Becquerel and RodierJ have especially directed attention to 

 its augmentation and diminution in diseased conditions of the 

 blood. According to these authors the amount of cholesterin 

 in 1000 parts of normal blood ranges from 0*025 to 0*200 (the 

 mean being O'OSS). There is an augmentation of the cholesterin 

 in the blood in old age, and in most acute diseases soon after 

 the occurrence of febrile symptoms, especially in inflammations 

 and in icterus. They have not discovered any physiological or 

 pathological condition in which there is a constant diminution of 

 this substance. 



Cholesterin always occurs in the brain, where it was first 

 discovered by Couerbe. Many subsequent observers have con- 

 firmed his observations. 



It also appears to be an integral constituent of pus ; at least 

 whenever I have allowed pus to become sour I have found tablets 

 of cholesterin in the decomposed mass ; moreover, Caventou, 

 Giiterbock, Valentin, and many others have detected it in fresh pus. 



Cholesterin is also very frequently found in dropsical exuda- 

 tions, especially in cysts ; I have recently, on two occasions, ana- 

 lysed the fluid of hydrocele discharged by incision ; both specimens 

 were semi-solid rather than fluid, and when stirred, formed beau- 

 tiful glistening bands. Their only morphological element was cho- 

 lesterin. 



Obsolete (chalky) tubercle, old echinococcus-cysts, such as 



* Untersuchungen iib. Galle. Erlangen, 1846. S. 58. 

 t Hannov. Ann. Bd. 5, H. I. 

 T Gaz. me'd. 1844, No. 47. ' 



