THE DIGESTIVE SYSTEM. 231 



constantly, but most markedly when alimentary matters 

 are in the mouth being masticated ; then the alternate 

 action of each gland, in accordance with unilateral masti- 

 cation, is marked. During abstinence the flow is about 

 a quarter as great as during mastication, and the fluid 

 passes generally into the reticulum. Though about equal 

 in size to the submaxillary, this gland produces four or 

 five times as much fluid [Sp. gr. 1*0108 (Lassaigne)]. 

 The flow of submaxillary saliva is unaffected during 

 rumination. The total quantity of mixed saliva produced 

 by an ox, taking three hours to feed and five to rumi- 

 nate, was estimated at 40,000 grammes during the eight 

 hours' mastication and 16,000 grammes during abstinence, 

 making a total of 56,000 grammes in twenty-four hours ; 

 this is probably under-estimated (Colin). Submaxillary 

 saliva is constantly produced during abstinence in small 

 quantities ; it is abundant during feeding, and its quantity 

 is related to the quality and taste of the food and to the 

 rapidity of mastication. Sublingual saliva may be obtained 

 from the accessory duct which runs from the posterior 

 lobe of the gland and opens near the submaxillary duct ; 

 it is constantly produced and is very viscid ; probably it 

 serves to coat the pellet of food. The well-developed 

 condition of the salivary apparatus accounts for the fact 

 that it is readily acted upon by even small doses of 

 mercury, whereby excessive secretion, Ptyalism, is pro- 

 duced. It also explains how sufiicient fluid is passed into 

 the rumen to thoroughly macerate the large quantity of 

 material it can contain. Mr. Cox, of Ashbourne, in the 

 'Veterinarian,' vol. xxv, p. 695, gives three cases of 

 ptyalism, due to paralysis for they were accompanied by 

 inability to raise the eyelid and a pendulous condition of 

 the ear and of the upper lip. A blister around the base 

 of the ear and a laxative dose cured these cases in a 

 month. In two other cases no paralysis was present. 



Inflammation of the Salivary Glands seldom takes 

 place as a disease in itself, though these organs are 

 generally involved in cases of sore throat. Cases of 

 Parotiditis sometimes are seen, but it is the lymphatic. 



