2o6 



A MANUAL OF VETERINARY PHYSIOLOGY 



The bolus in the mouth may weigh from ioo to 120 grammes 

 (3 to 4 ounces), and it is projected into this cavity with such 

 force that if the mouth is open it may drop out. Its remastica- 

 tion occupies about fifty seconds ; it is then reswallowed, and 



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passes to the third compartment, or, if not sufficiently com- 

 minuted, it returns to the rumen, and is once more remasticated. 

 The ascent and descent of the bolus in the neck may be 

 readily seen, and Colin has estimated that each of these requires 

 1*5 seconds, while an equal period is required for the formation 

 of a fresh bolus. On this data, from the time the bolus is pre- 



