116 FATS. 



decant or filter. On cooling, the cerebric acid will be 

 deposited, and must be washed with cold ether and 

 purified by recrystallising from boiling ether. 



4. Warm the alcoholic solution of stearate and 

 palmitate, add cautiously alcohol containing sulphuric 

 acid till all the potassium has been precipitated as 

 sulphate. Filter, evaporate down, and separate the 

 stearic and palmitic acid by crystallisation from 

 absolute alcohol, in which the former is the less 

 soluble. 



5. The ethereal solution must be evaporated to 

 dryness, boiled with caustic potash till saponified, and 

 decanted from undissolved cholesterine. 



6. The cholesterine is purified by crystallisation from 

 boiling alcohol. 



7. The soap, containing oleic and margaric acids, 

 must be salted out by potassium chloride, again 

 dissolved and salted out, dried, powdered, and di- 

 gested with cold alcohol, in which oleate is the more 

 soluble. From the salts thus separated the acids are 

 obtained by sulphuric acid as above. The margaric 

 acid may be purified by crystallisation from alcohol. 

 Digest the oleic acid at 100 C. with half its weight of 

 finely-powdered lead oxyde, mix the resulting mass 

 with two volumes of ether, allow to stand ; decant 

 from any undissolved matter, shake the solution with 

 enough dilute sulphuric acid to combine with nearly 

 all the lead, separate off the solution of oleic acid in 

 ether, and drive off the ether by distillation. 



Fibrine of blood. 1 . Beat briskly a quantity of fresh- 



