54 DB. W. EUTHEEFOBD ON THE (ESOPHAGUS 



Bartbolinus and Grew's accounts somewhat resemble this ; but 

 they thought that there was an internal and also an external 

 series of double spirals. Ducernus, Delphinus, and Willis adopted 

 Stenson's description; and Peyer's account, though evidently 

 intended to be original, does not differ from Stenson's, excepting 

 that it is a more lucid and intelligible exposition of a mistaken 

 notion as to the structure. 



Monro (Secundus) has, in a thesis on dysphagia, mentioned 

 the fact that the muscular fibres in the Euminant's gullet cross 

 each other like the lines of the letter X. But this was nothing 

 new ; it had been pointed out long before ; and it is a fact which 

 any one might perceive almost at a glance. 



Dr. Spencer Cobbold's description* is the latest. He says 

 that the muscular fibres are arranged in two layers, the outer 

 "transversely circular," the inner " obliquely longitudinal." 



These descriptions are all incorrect. Certainly Stenson's is 

 nearer the truth than any of the others ; but it is, nevertheless, 

 wide of the mark. 



After prolonged and careful dissection, I feel convinced that 

 the following wiU be found to be the true description. 



The muscular structure of the oesophagus consists of two 

 layers of fibres running in an oblique direction. The fibres of 

 both layers do not, however, run in the same direction, but cross 

 each other like the letter X. The two layers are everywhere 



Fig. 1. 



External layer. ^^^^^M ^^^^ Internal layer, 



separable, except at two lines, which are exactly opposite each 

 other, and run from one end of the gullet to the other, dividing 

 it longitudinally into two symmetrical halves. (Plate III. 

 fig. 2.) 



These lines I shall call the decussations; for there the two 



layers intermingle, the inner layer of either side passing out to 



become the outer layer of the opposite side ; that is to say, the 



inner layer of one side passes outward, to become the outer layer 



* Todd's Cyelopffidia of Anatomy and Physiology. 



