RUMINATION. 329 



saliva each in one-quarter of an hour. Besides keeping the food in the 

 rumen moist and lubricating the oesophagus, the saliva secreted during 

 abstinence and the second mastication does not all pass into the rumen, 

 but some of it also passes into the many plies, and so serves to keep the 

 oesophageal gutter lubricated. 



As soon as the mastication of the cud is complete, and the food thus 

 sufficiently comminuted and impregnated with a large amount of liquid, 

 it is a second time swallowed, the mechanism again being the same 

 as was described under the heading of deglutition. Only about four 

 seconds elapse from the time of deglutition of one bolus before the next 

 is formed and ascends to the mouth. Of this period, probably one and a 

 half seconds each is occupied by the descent of the bolus, the formation of 

 a new bolus, and the ascent to the mouth. When the cud has been swal- 

 lowed a second time it is now so finely divided that it is able to pass 

 through the opening between the second and third stomachs. It there- 

 fore largely follows the course of the oesophageal canal, and passes 

 rapidly into the manyplies, and from there into the true stomach, to be 

 subjected to the action of the gastric juices. Part of it, however, pos- 

 sibly falls directly into the rumen and reticulum, to be mixed with the 

 materials contained in these cavities. 



In order that rumination may take place the stomach must be dis- 

 tended with food, otherwise the walls of the rumen will be flaccid and 

 the abdominal muscles will be ineffective in aiding in the passage of the 

 bolus upward through the oesophagus. Since, then, no digestion or 

 absorption occurs within the first three gastric compartments, an animal 

 under such a condition might die of hunger with its rumen still almost 

 filled with food. On the other hand, the paunch must not be very much 

 distended, or its walls will be paralyzed and will be prevented from re- 

 acting on its contents. Ruminant animals must always be well supplied 

 with water, and their secretion of saliva must be active. Rapidly grown 

 grasses from irrigated meadows distend the rumen far more in propor- 

 tion to their solid elements than other forms of food. The distended 

 paunch, however, soon diminishes in size, and then appears very empty, 

 and animals cannot ruminate as effectually as with harder and drier food, 

 as a certain bulk is required to permit of regurgitation. Rumination 

 does not, as a rule, commence until after the animals have been watered, 

 unless fed on green fodder or succulent roots, and even then they some- 

 times require water. 



The position which the ruminant animal assumes during the act of 

 rumination is common to all ruminants, and is very characteristic. The 

 animal reclines slightly on one side, resting more or as much on the 

 chest as on the belly, the anterior limbs flexed under the chest, and the 

 posterior limbs brought forward and partly under the abdomen. 



