278 CATTLE. 



CHAPTER XII. 



THE STRUCTURE AND DISEASES OF THE GULLET AND STOMACHS. 

 THE CESOPHAGUS, OR GULLET. 



The food having been forced along the posterior part of the mouth 

 by the consecutive action of the tongue and the muscles of the 

 pharynx, reaches the oesojjhagus, or gullet. This tube extends from 

 the mouth to the stomachs, and conveys the food from the one to 

 the other. In cattle this is true in a double sense ; for not only does 

 the food descend from the mouth to one of the stomachs, when it is 

 jBrst gathered, but is returned for a second mastication, and after- 

 wards, a third time, traces the same path to its destination in the 

 true digestive stomach. There is some peculiarity of structure in 

 the oesophagus, in order to prepare it for this increased duty. 



We first observe the great thickness and strength of the gullet in 

 the ox. The outer coat of loose cellular substance is yielding and 

 elastic. The second coat is a muscular one, and of great substance 

 and power. Its increased substance enables it to dilate, when the 

 laro-e pellets of rapidly plucked grass, or pieces of parsnip or potato, 

 or other hard roots, enter it ; and the same increase of muscular 

 substance enables it to contract more powerfully on such food, and 

 pass it on to the stomach. There are two layers of muscles in the 

 gullet of all our domesticated animals, and the fibres of the outer 

 and inner layer run in different directions, and with plain and mani- 

 fest reference to the natural food and habits of the animal. 



The fibres of both layers of the muscular coat are spiral, but they 

 wind their way round the gullet in contrary directions, admitting 

 thus of the lengthening and shortening of the tube in grazing and 

 swallowing ; ofjfering, perhaps not so much pressure on the food, 

 and which the lazy mastication and rumination of the animal does 

 not require ; and permitting a great deal more dilitation when some 

 large and hard substance finds its way into the gullet. 



The inner coat, a continuation of the membrane of the pharynx, 

 is quite cuticulir, smooth, and glistening. It lies in longitudinal 

 plaits, so wide and numerous as sufficiently to dilate wh^n the food 

 passes, and to add very little to the obstacle when a porl'on of food 

 unusually large is arrested in its passage. 



