324 STRUCTURE OF THE SHEEP. 



by the muscular-strength possessed by this viscus. In op 

 position to this opinion it may be urged that it requires but 

 little more force to raise the food to the root of the (Esopha- 

 gus than to the entrance of the reticulum, and also, that the 

 contents of the second stomach are of a more fluid nature 

 than those of the first. It is not to be supposed that all the food 

 taken is again ruminated ; it is only the hard indigestible 

 portion that undergoes the process. Rumination is assisted 

 by the pressure of the abdominal muscles and the diaphragm, 

 and the larger and more distended the stomachs the more 

 likely they are to receive assistance from these aids. Keep- 

 ing these facts in view, we are inclined to believe that both 

 the first and second stomach may have equal power in the 

 process of rumination. In accordance with this idea we must 

 suppose that a mass of food is raised from the rumen into the 

 oesophagean canal, that the hardest and driest portion is se- 

 lected by the root of the oesophagus, and that the other part 

 passes onwards, and whilst some portion may reach the third, 

 the great part will fall, as it were, through the trap-door into 

 the second stomach, there to undergo a further macerating or 

 digesting process. When this viscus isi moderately full it 

 will contract on its contents, and first squeeze out the fluid 

 portion, which will, of course, pass onwards into the third 

 and fourth stomachs, whilst the solid part will be embraced 

 by the oesophagus and returned to the mouth. 



It is evident that the functions of the oesophagus are much 

 more onerous than in non-ruminating animals, and according- 

 ly it is furnished with more muscular power ; the lower por- 

 tion particularly is surrounded with spiral muscles, by which 

 the selected pellet is first sent upwards. 



It is not unlikely that some portion of the food may be 

 submitted two or more times to the process of rumination. 



It is -probable that the most liquid portion of the food at 

 once enters the fourth stomach, and that of a harder nature 

 the maniplus. The singular construction of this viscus evi- 

 dently shows that it must efiect an important office, and it 

 has been found that in animals which through life have never 

 thriven well, notwithstanding that they have consumed a lar- 

 ger quantity of food than other beasts, the maniplus has been 

 imperfectly formed, the plaits being short so as to afibrd con- 

 siderably l^s surface than usual. The use of this stomach, 

 therefore, is to detain the food, to press it between its foMs 



J to soften it by the secretion afforded by its extensira 



