XV.] SALIVARY GLANDS AND PANCREAS. SALIVA. 1G1 



D. SALIVA. 



1. Look at a little fresh saliva under the microscope 

 with a high power. Disregarding the flat epi- 

 thelial cells from the mucous membrane of the 

 mouth, note the salivary corpuscles ; they are 

 larger than the ordinary white blood-corpuscles, 

 but in other respects closely resemble them. In 

 many, a very active Brownian movement of the 

 granules within the corpuscle may be observed. 



2. Test with neutral litmus paper the reaction of a 

 drop of saliva, it will be found to be alkaline. 



3. Induce the secretion of saliva by chewing a small 

 piece of india-rubber tubing, by filling the mouth 

 with ether vapour, or by rubbing the tongue 

 with a crystal of tartaric acid. 



If time allows let the saliva stand until the 

 turbidity has settled down into a sediment. To 

 a few c.c. of the fluid add strong acetic acid; 

 mucin will separate out as a stringy mass, 

 which does not dissolve in excess of acid. 

 Shake gently, or stir it with a glass rod the 

 mucin will form a clump, remove it, and if the 

 fluid is cloudy, filter. 



4. To the clear fluid add a drop or two of a strong 

 solution of potassium ferrocyanide. The slight 

 precipitate which results indicates the total 

 quantity of proteids present (cp. Lesson III. 

 16). If the reaction is not obvious, test 

 another small portion with Millon's reagent. 



L. 11 



