PTYALISM. 119 



in the ox. Mathieu saw peculiar attacks of salivation in the 

 autumn of 1852, from horses, cattle, and sheep eating clover 

 and esparcet, which had become of a brown colour, and this 

 was believed to be due to a change in the chlorophyl in the 

 leaves. Two pounds of such hay caused horses to lose from 

 30 to 36 pounds of saliva in from five to six hours, giving 

 rise to great thirst. 



When any source of irritation exists in the mouth, the dis- 

 charge of saliva is often very great. 



Treatment in all such cases consists in removing the cause, 

 and using locally cold water injections into the mouth, coupled 

 with frictions around the salivary glands, with slightly stimu- 

 lating embrocations. 



The saliva undergoes serious changes in disease. It be- 

 comes poisonous in rabies, and preserves its poisonous pro- 

 perties about twenty-four hours after the death of the 

 animal; but Count Salm has experimented on the dried 

 foam from the mouth, and has been successful in communi- 

 cating the disease.* 



The saliva becomes charged with the virus of epizootic 

 aphtha, with the poison of giossanthrax, and is perverted also 

 in the contagious typhoid or steppe disease. 



Dilatations of Salivary Ducts. Hertwig states having 

 frequently seen distension of a parotid duct in the horse 

 caused by some injury to the canal, obstructions of various 

 kinds, and, especially, produced by salivary concretions. 



Ranula is a condition referred to by several veterinary sur- 

 geons, and I have seen several remarkable cases. It consists 

 in dilatation of one of the ducts of the sublingual gland. 

 The tumour has been described as an abscess or cyst, but it 

 is distension of a duct by a ropy liquid. I remember one 



* See the Veterinarian's Vade-Mccum, page 216. 



