SOME GENERAL CHARACTERS OF SALIVA. 



SOME GENERAL CHARACTERS OF SALIVA, AND ITS MICROSCOPIC 

 CONSTITUENTS. 



The viscidity of saliva, secreted by mucous glands, is generally in 

 proportion to the percentage of mucin which it contains. This, of 

 course, would not be the case, if the amount of alkaline salt in the 

 saliva increased in much larger proportion than the amount of mucin, 

 for, with a given quantity of mucin, the viscidity of the fluid varies with 

 the amount of the solvent. 



Saliva, from albuminous or from mixed glands, may be either watery 

 or thick, irrespective, within certain limits, of the percentage of organic 

 substance present. Sublingual saliva and parotid saliva of the dog, 

 when they have a high percentage of organic substance, have a tendency 

 to turn into a jelly-like mass, and this may further separate into a clot 

 and clear fluid. 



In very watery saliva, freshly secreted, which has not been allowed 

 to stand in the ducts, and which is examined without delay, nothing is 

 to be seen under the microscope. 



When saliva is allowed to stand a short time in the ducts, car- 

 bonic acid is given off from it, and, in consequence, calcium carbonate 

 is precipitated ; the precipitate renders the saliva cloudy, and under 

 the microscope appears as very fine particles, or groups of particles. 

 On irrigating such a specimen with dilute mineral acid, the particles 

 are dissolved. The saliva also may contain leucocytes, and will certainly 

 do so if it has been allowed to stay long in the gland ducts. In ordinary 

 experimental conditions, leucocytes collect in the connective tissue of 

 the glands, and migrate, at times in large numbers, into the ducts. The 

 leucocytes at first show amoeboid movement ; later, they swell, become 

 vacuolated, and form the bodies which have been called salivary cor- 

 puscles. The saliva may also contain some cells from the ducts 

 which have been separated or injured by insertion of the cannula, 

 some isolated nuclei, either of duct cells or of leucocytes, and. occasionally 

 a few small fat globules. 



