298 STOMACHS OP THE SHEEP. 



"Let us now observe the course pursued by the food, and 

 the process to which it is submitted, after rumination. It 

 glides over the trap-doors which open into the first and second 

 stomachs. As it passes over the floor of the third, or the 

 maniplus, the pendant leaves of this viscus, armed with their 

 beak-like protuberances, seize the advancing mass, and 

 squeezing out the fluid and the more finely comminuted 

 portions of the food which escape with it, conxmence tritura- 

 ting the bulkier fibrous portions between their folds. Their 

 bony papiUse give to these folds something of the mechanical 

 action of rasps, in grinding down the vegetable fiber. The 

 food being now reduced to an entirely pultaceous state, passes 

 into the fourth stomach, or abomasum, where it is acted upon 

 by the gastric juice, and converted into chyme. The amount 

 of food found between the folds of the maniplus, after death, 

 depends upon the time that has elapsed since rumination. It 

 is dry and hard, compared with the contents of the other 

 stomachs. 



"The entrance to the fourth stomach— the cardiac opening 

 — is closed .against regurgitation or vomiting, by a sort of 

 valve, composed of a portion of one of the rugaa, before alluded 

 to, which line the interior of this stomach. The pylorus is 

 also closed by a valve, which prevents a premature passage 

 of the contents of the stomach into the intestines. 



"Before the duodenum enters into (or changes its name 

 to) the jejunum, and about 18 inches from the pylorus, it is 

 perforated by the biliary duct — ductus eholedochus — which 

 brings the bile eliminated by the liver, from the gall-bladder, 

 and also the fluid which is secreted by the pancreas, or sweet- 

 bread, which last is introduced into the biliary duct two 

 inches from its entrance into the duodenum, by another duct 

 or smaU tube. The compound fluid thus introduced into the 

 duodenum exercises various important offices in the digestive 

 and assimilating processes. The bile is supposed to aid in the 

 separation of the chyme into chyle and fecal matter — or the 

 nutritive parts of the food which are assimilated into blood, 

 from the innutritions parts which are dischai^ged as excrement. 

 It also prevents a putrid decomposition of the vegetable 

 contents of the intestines, and serves various other useful 

 purposes. 



" The chyle — a white albuminous fluid, with a composi- 

 tion difiering but little from that of blood — is taken from the 

 intestines by a multitude of minute ducts called lacteals, which 

 traverse the mesentary, constantly imiting as they advance, 



