86 BRAIN. 



4. Extract cerebrine and protagon with boiling 

 alcohol, as directed under those bodies. 



5. From the cold ether extract containing chole- 

 sterine and lecithine which is obtained in the preparation 

 of cerebric acid, lecithine is isolated by the process 

 given under that substance, any great excess of the 

 platinic or cadmium chloride being avoided. The 

 filtrate from the precipitated lecithine compound is 

 boiled with excess of plumbic hydrate and filtered. 

 On cooling a copious crystalline deposit will form, from 

 which pure cholesterine may be obtained by recrystalli- 

 sation from boiling alcohol, 



6. Eub brain-matter in a mortar with water con- 

 taining enough sodium chloride to prevent cerebrine 

 and cerebric acid from forming an emulsion ; filter 

 the mixture. The clear filtrate will contain potassium- 

 albumen or casein, which may be precipitated by 

 sulphuric acid not in excess. From the filtrate 

 addition of a few drops of acetic acid and boiling will 

 throw down albumen if present. 



7. Rub in a mortar to a thin milk with excess of 

 baryta water, heat till just coagulated, filter, remove 

 the main bulk of the baryta from the filtrate by a 

 current of carbonic acid, and the last traces by exact 

 precipitation with sulphuric acid and evaporate to a 

 low bulk. Divide this extract into two portions. 



8. One portion of the extract distil with dilute 

 sulphuric acid to obtain the volatile acids, acetic and 

 formic. Examine them as directed under those 

 bodies. 



9. The other portion of the extract heat with eth 



. 



