14 



Saponins and Sapotoxins 

 These are neutral nitrogenous bodies characterized by foam- 

 ing with water, emulsifying fats and laking blood corpuscles. A 

 few are glucosides. The term saponin is given to the least poison- 

 ous of the group and sapotoxin to the most poisonous. 

 Experiments: Use Tincture of Soap Bark. 



1. Shake a few drops of the above tincture with a few mils of 



water. Note results. 



2. Place about 5 mils of cotton seed oil in a test-tube. Add 25 



drops of tincture of soap bark. Shake and note results. 

 Add a little alcohol. Results. Is tihe emulsion perma- 

 nent? 

 3. To a test-tube add 5 mils of a 0.9% solution of sodium chlor-' 

 idewith 1/10% solution of saponin, then add two or three 

 drops of defibrinated blood. Note results. 

 4. Repeat the experiment without using the saponin solution. 



Gums 



Gums are amorphous transparent substances belonging to the 

 group of carbohydrates. Some dissolve in water and others only 

 swell up and form a jelly. All are insoluble in alcdhol. 

 Experiment : 

 1. Test solubility of acacia and tragacanth in water and alco- 

 hol. 



Tannins 



Tannins are the astringent properties of many plants. They 

 exist chiefly as tannic and gallic acids. 



Experiments: Use 1% solution of tannic acid. 



1. To a few mils of tannic acid solution add a drop of ferric 



chloride solution. Note a green blue black color. Dilute 

 until transparent. Add a few drops of sodium hydrate 

 solution. Garnet color. 



2. Add a little solution of lead acetate to a solution of tannic 



acid. Results. 



3. Add a little solution of sodium hydrate to a solution of tan- 



nic acid. Results. 



