Insalivation. I 7 



certain alimentary matters. Its power of alter- 

 ing the constitution of compounds is purely 

 a chemical action, and is most peculiarly well 

 marked upon those of a starchy character, 

 abundance of which are found in the food upon 

 which horses and cattle subsist. Through this 

 influence they are converted into a principle 

 called dextrine, and subsequently into grape sugar. 



The salivary glands are under the control of 

 the nervous system. In the human subject, the 

 sight or smell of food of an agreeable character 

 is sufficient to cause a copious flow to the mouth ; 

 hence the common expression " the mouth 

 waters." 



Saliva is secreted abundantly. The exact 

 amount of this fluid which is formed is not easily 

 obtained. A large horse is supposed to secrete 

 84lbs. per day, an ox 1021bs. Mr. Hunting ob- 

 tained half a gallon, or about five pounds in half 

 an hour. 



The uses of saliva are important and manifold. 

 First, we have an abundant flow; second, its 

 peculiar solvent power ; third, its chemical action 

 in converting starchy matters into sugar; fourth, 

 its lubricating qualities during the presence of 

 absorbing, or coarse and rough, substances; fifth, 

 it is secreted in major part during mastic ation y 

 and continues as long as that act is carried on. 



This category of properties in a simple-looking 

 fluid like saliva must have been conferred for a 

 beneficial purpose. 



