CIIOLE8TERINE. 



447 



FIG. 136. Cholesterine extracted from the Ule ; 

 objective. 



inch 



sulphuric acid, it strikes a peculiar red color, which is mentioned by some as characteristic 

 of cholesterine. We have found that it possesses this character in common with the so- 

 called seroline. 



Cholesterine may easily and certainly be recognized by the form of its crystals, the char- 

 acters of which can be made out by means of the microscope. They are rectangular or 

 rhomboidal, exceedingly thin and transparent, of variable size, with distinct and generally 

 regular borders, and frequently are arranged 

 in layers, with the borders of the lower stra- 

 ta showing through those which are super- 

 imposed. This arrangement of the crystals 

 takes place when cholesterine is present in 

 considerable quantity. In pathological speci- 

 mens, the crystals are generally few in num- 

 ber and isolated. The plates of cholesterine 

 are frequently marked by a cleavage at one 

 corner, the lines running parallel to the bor- 

 ders; and frequently they are broken, and 

 the line of fracture is generally undulating. 

 Frequently the plates are rectangular, and 

 sometimes they are almost lozenge-shaped. 

 It is by the transparency of the plates, the 

 parallelism of their borders, and their ten- 

 dency to break in parallel lines, that we rec- 

 ognize cholesterine. Crystals of cholesterine 

 melt at 293 Fahr., but they are formed again 

 when the temperature falls below that point. The determination of the fusing-point is 

 one of the means of distinguishing cholesterine from seroline, which latter fuses at 90 8'. 



Without considering in detail the processes which have been employed by other 

 observers for the extraction of cholesterine from the blood, bile, and various tissues of the 

 body, we shall simply describe the method which has been found most convenient in the 

 various analyses we have made for this substance. In analyses of gall-stones, the process 

 is very simple ; all that is necessary being to pulverize the mass, extract it with boiling 

 alcohol, and filter the solution while hot, the cholesterine being deposited on cooling. 

 If the crystals be colored, they may be redissolved and filtered through animal charcoal. 

 It is only when tnis substance is mixed with fatty matters, that its isolation is a matter 

 of any difficulty. In extracting cholesterine from the blood, we have operated on both 

 the serum and clot, and, in this way, we have been able to demonstrate it in greater quan- 

 tities in this fluid than have been observed by others, who have employed only the serum. 

 The following is the process for quantitative analysis, which was fixed upon after a 

 number of experiments : 



The blood, bile, or brain, as the case maybe, is first carefully weighed, then evaporated 

 to dryness over a water-bath, and afterward pulverized in an agate mortar. The powder 

 is then treated with ether, in the proportion of about a fluidounce for every hundred grains 

 of the original weight, for from twelve to twenty-four hours, agitating the mixture occa- 

 sionally. The ether is then separated by filtration, throwing a little fresh ether on the 

 filter so as to wash through every trace of the fat, and the solution is set aside to evaporate. 

 If the fluid, especially the blood, have been carefully dried and pulverized, when the ether 

 is added it divides it into a very fine powder and penetrates every part. After the ether 

 has evaporated, the residue is extracted with boiling alcohol, in the proportion of about 

 a fluidrachm for every hundred grains of the original weight of the specimen, filtered 

 while hot into a watch-glass, and allowed to evaporate spontaneously. To keep the fluid 

 hot while filtering, the whole apparatus may be placed in the chamber of a large water- 

 bath, or, as the filtration is generally rapid, the funnel may be warmed by plunging it 



