78. Blue color disappearing on heating and returning on 

 cooling indicates starch. 



79. Mphogany-brown color disappearing on heating and 

 returning' on cooling indicates dextrin or glycogen. (The 

 latter is precipitated by the addition of basic lead acetate). 



80. Test for reducing sugar by Trommer's test. 



81. Try the phenyl-hydrazine test. (53.) 



VII. 



82. Salivary Digestion. To obtain mixed saliva. Chew 

 a small piece of parrafin or chewing gum, or inhale ether for 

 a short time to stimulate the flow of the secretion. Collect 

 it in a graduate until you have about 30 cc. Note that, in 

 a short time, more or less of a sediment occurs due to the de- 

 position of epithelial cells, debris of food, bacteria, etc. 

 Numerous air bubbles are usually present upon the surface. 



Filter. Is it translucent ? Is there any great amount of 

 viscidity? What is its reaction to litmus paper? The 

 specific gravity is 1002 — 1006. 



83. Add acetic acid. A precipitate indicates mucin. Not 

 soluble in excess. Filter. 



84. With the filtrate from 83, test for traces of proteids 

 with the xanthoproteic reaction and Millon's test. 



85. To a few drops of .saliva in a porcelain evaporating 

 dish add a few drops of dilute acidulated ferric chloride, — a 

 red coloration indicates the presence of sulphocyanide of 

 potassium, the color does not disappear on heating, nor on 

 the addition of an acid, but is dLscharged by mercuric 

 chloride. Meconic acid gives a similar color, but it is not 

 discharged by mercuric chloride. The sulphocyanide is 

 present only in the secretion from the parotid gland. 



86. Test for chlorides by adding to the saliva a few drops 

 of nitric acid followed by a few drops of silver nitrate. A 



