12 



solution with dilute sulphuric acid and test with mercuric 

 potaJssium iodide. 

 Explain your results. 



Shake the etheral solution with a little of the dilute sul- 

 phuric acid, and test the acid solution (at bottom of tube) 

 with the above reagent. Explain results. 

 Draw conclusions from the above experiments. 

 7. Boil 10 mils of quinine solution for a few minutes with 1 

 mil of sulphuric acid. Neutralize with solution of so- 

 dium hydrate, and apply Pehling's test for reducing 

 sugars. 



GrLUCOSIDES 



Definition : — Glucosides are those plant principles which when 

 treated with dilute acids or submitted to the action of ferments split 

 up and yield glucose as one of the decomposition products. Many 

 but all do not contain nitrogen. A few are alkaloidal but most are 

 neutral. 



Experiments : 



1. Test a 1% solution of glucoside (Use Salicin) with Fehling's 



solution. 



2. Add 1/5 of volume of dilute sulphuric acid to another por- 



tion, boil 10 minutes in a water bath. Render alkaline 

 with solution of sodium hydrate and apply Fehling's 

 test. 



3. To a third portion of the solution add a little saliva and 



heat at 40°C. for one-half hour. Apply Pehling's test. 



4. Apply previous reagents for the precipitation of alkaloids, 



Tabulate results. 



Resins 



These are solid plant substances, usually of an acid nature, in- 

 soluble in water, soluble in an alkali and water and in alcohol. The 

 definition of the pharmaceutic class "resins" is those plant pro- 

 ducts soluble in alcohol, insoluble in water, obtained either as a 

 residue from the distillation of an oleoresin or by pouring a concen- 

 trated alcoholic extract into water or acidulated water. If they 

 occur mixed with a volatile oil they are termed oleoresins, if mixed 



