276 



PHYSIOLOGY OP THE DOMESTIC ANIMALS. 



glands secrete alternately during mastication, both in the horse and 



ruminant animals, and, in all probability, also in the omnivora, the 



secretion occurring on the side 

 on which mastication is taking 

 place. Thus, when mastication 

 is taking place between the right 

 molar teeth, then it is the right 

 parotid alone, in the horse, which 

 secretes, and it is the right 

 parotid in the ruminant which 

 has the highest activitj'. Ex- 

 periments conducted by Colin, 

 by making a fistula of the parotid 

 ducts in the horse and the ass, 



have demonstrated the truth of these statements. The following tables 



represent some of his results : — 



Fig. 114.— Pakotid Fistula in the Horse. 



(Bernard.) 



a, duct of Steno, with cannula inserted, and rubber bag for 



collecting the saliva. 



Experiment. Time in Minutes. Right Parotid. 

 1. Horse, 15 910 grammes. 



Left Parotid. Side of Mastication. 

 200 grammes. Right. 



" 



15 



580 



320 



Eight 



' ' 



15 



250 



700 



Left. 



2. Horse, 



. 15 



570 



620 



Left. 



" 



15 



510 



820 



Left- 



11 



15 



500 



800 



Left. 



" 



15 



480 



750 



Left, 



( * 



. 15 



720 



420 



Right 



** 



15 



540 



800 



Left. 



1 ' 



. 15 



600 



740 



Left, 



3, Horse, . 



. 15 



620 



260 



Right 



' ' 



. 10 



330 



200 



Right 





. 5 



200 



120 



Right 



* ' 



. 15 



410 



230 



Right 





. 10 



60 



320 



Left. 



' ( 



5 



20 



150 



Left. 



" , 



. 15 



• 



130 



520 



Left. 



4. Horse, . 



. 5 



160 



85 



Right. 



1 ' 



. 6 



150 



235 



Left. 





4 



160 



40 



Right. 





4 



115 



70 



Right. 





4 



95 



165 



Left. 



" 



6 



80 



210 



Left. 



5. Horse, 



3 



50 



110 



Left. 



1 ' 



6 



200 



50 



Right. 



" 



4 



30 



100 



Left. 





5 



200 



30 



Right. 



6. Ass, 



15 



120 



10 



Right. 



" 



15 



110 



60 



Right. 





15 



80 



170 



Left. 



" 



15 



150 



15 



Right. 





15 



30 



160 



Left 



" 



15 



55 



135 



Left. 





15 



50 



165 



Left. 



