FATS. 115 



5. Another portion of this insoluble matter should 

 be digested with dilute sulphuric acid, and the solution 

 examined spectroscopically for products of decomposi- 

 tion of hematine or other matters. 



6. Digest the dried faeces in chloroform : no cholo- 

 pha3ine can be extracted, showing that the biliary 

 matters, if present, had been changed in composition 

 in passing through the intestine. 



7. Distil the fresh undried faeces with dilute sul- 

 phuric acid ; a fetid distillate will pass over, containing 

 volatile acids (q.v.) and an essential oil. 



8. Burn dried faeces and analyse ash. Notice pre- 

 dominance of potash over soda. 



Fats. Extraction and separation of animal fats. 1 . 

 Exhaust the substance (concentrated to an extract, if 

 liquid) with boiling 90% alcohol containing enough 

 sulphuric acid to decompose any soaps that may be 

 present, evaporate the mixed filtered extracts to near 

 dryness, treat with three or four volumes of ether, 

 allow to stand for some time with frequent agitation, 

 decant or filter. 



2. The matter insoluble in cold ether may contain 

 cerebric acid, palmitin, and stearin. Boil with caustic 

 potash solution till saponified, separate out the soaps 

 by adding solid potassium chloride, collect, press, dry 

 at 100 C., reduce to as fine a powder as possible, and 

 digest with cold alcohol. Potassium cerebrate will 

 remain undissolved. 



3. "Wash the cerebrate with cold alcohol, decompose 

 by boiling alcohol containing sulphuric acid, and 



