1 2 Mr. T. Taylor on a ?icw Species of Biliary Calculus, 



stillation in a small retort: the liquid remaining in the retort, 

 when cold, formed a soft crystalline mass, composed of bril- 

 liant plates and having a pearly lustre, very much resembling 

 margaric acid. 



This substance, when fused and kept for some time in 

 vacuo over sulphuric acid, weighed 8'88. It melted at 136° 

 Fahr., and on cooling became a crystalline solid, red- 

 dened litmus paper, and was easily soluble in a cold solu- 

 tion of caustic potass ; the solution when concentrated was 

 ropy and gelatinous; when dilute it formed a slightly milky 

 mixture with minute glistening particles floating in it; on 

 the addition of an acid, the substance was thrown down in 

 the form of white flakes, which possessed the same properties 

 as before solution. When boiled with the alkaline carbonates, 

 it was dissolved, with the escape of carbonic acid. By re- 

 dissolving it in hot alcohol, crystalline plates were deposited 

 on cooling, which after washing with cold spirit fused at 

 about 140°. The low fusing point of this substance evidently 

 indicates the presence of oleic acid. In order to ascertain 

 whether the crystals fusible at 140° were pure margaric 

 acid or stearic acid rendered more fusible by an admixture 

 of oleic acid, they were again dissolved in warm spirit, and 

 the crystals as soon as formed dried by compression between 

 folds of blotting paper ; by repeating this process two or three 

 times, the fusing point was raised to nearly 160°. This must 

 therefore be regarded as pure stearic acid ; and as I find that 

 both stearic and margaric acids require to be several times 

 recrystallized from their alcoholic solutions to free them from 

 even small quantities of oleic acid, and as no decided indi- 

 cation of the presence of margaric acid could be detected 

 in the mother liquors, I am inclined to believe that oleic acid 

 had only been separated by the above treatment, and that con- 

 sequently margaric acid did not enter into the composition of 

 the calculus. It would however be impossible to speak de- 

 cidedly on this point. 



The result of the analysis is as follows : 



Stearic acid mixed with a small pro-1 _ „- 



portion of oleic acid J 



Lime 1*17 



Soda with a trace of lime 0*05 



Yellow colouring matter ofihe bile 0*86 



Inspissated bile 0*60 



Mucus of the gall-bladder 0'24 



12-27 



Loss 53 



12-80 



