180 DIGESTION. 



horse, Bernard found that after the ducts of Steno had been 

 divided, the portions of food, which were collected by an 

 opening into the oesophagus as they were swallowed, were 

 not coherent and were passed into the stomach with great 

 difficulty. The time occupied in eating about three-quarters 

 of a pound of oats was twenty-five minutes ; while before 

 the section of the salivary ducts, a pound of oats was eaten 

 in nine minutes. 1 



The secretions from the submaxillary and sublingual 

 glands and the small glands and follicles of the mouth, being 

 more viscid and less in quantity than the parotid secretion, 

 penetrate the alimentary bolus less easily, and have rather 

 a tendency to form a glairy coating on its exterior ; ag- 

 glutinating the particles on the surface with peculiar tena- 

 city. 



When the process of mastication and insalivation is com- 

 pleted, and the food is passed back into the pharynx, it meets 

 with the secretion of the pharyngeal glands, which still fur- 

 ther coats the surface with the viscid fluid which covers the 

 mucous membrane in this situation, thus facilitating the first 

 processes of deglutition. 



It has been observed that the saliva has a remarkable 

 tendency to entangle bubbles of air in the alimentary mass. 

 In mastication, a considerable quantity of air is mixed with 

 the food, and this undoubtedly facilitates the penetration of 

 the gastric juice. It is well known that moist, heavy bread, 

 and articles that cannot become impregnated in this way 

 with air, are not easily acted upon in the stomach. 



1 BERNARD, Legons de Physiologic Experimental, Paris, 1856, p. 146. 



