56 



DE. W. BTJTHEBrORD ON THE (ESOPHAGUS 



The great difficulty in ascertaining the structure lies in tracing 

 these non-decussating bundles from one decussation to the other ; 

 for an intermingling of the fibres of the outer layer takes place 

 between the decussations (Plate III. fig. 2, r). The non-decus- 

 sating bundle (which is external to everything at the one decussa- 

 tion), when traced downwards, e.g., gets below the non-decussating 

 bundle coming up from the other decussation ; while the latter, 

 in turn, gets below the former ; so that at both decussations 

 the non-decussating bundles are necessarily external, while the 

 decussating bundles are internal {vide Fig. 7). 



It would be an easy task to trace . -^'S- ^• 



Diagrammatic representation 



of the course of the fibres in 

 one lateral half of the gullet, 

 including both d ecussations. 



these bundles in the outer layer, did 

 the fibres of both bundles not inter- 

 mingle as they cross each other ; but 

 the bundles break up into their finest 

 fibres, thereby rendering the interdigi- 

 tation very minute and difficult to trace 

 (Plate III. fig. 2, r). I have often 

 failed to do so, but I have succeeded a 

 sufficient number of times to warrant 

 my advancing the above description as 

 correct. Now, all the fibres of the 

 inner layers, whether traced upwards 

 or downwards, will always be found 

 to decussate (except at the lower end 

 of the cesophagus) ; and if they be 

 traced onwards in the outer layers, they 

 will be found to form the non-decus- 

 sating bundles at the next decussation 

 {vide Pig. 7, a' & b'). This being true, 

 the structure is simply this: — Each 

 bundle of fibres forms a perfect loop, 

 which crosses the cesophagus obliquely three times (Pig. 6). 

 That is to say, a bundle of fibres (a, Pig. 6) in the outer 

 layer, which runs over a decussation without decussating, when 

 traced round to the other decussation (c) is there found to de- 

 cussate and pass into the inner layer (pe), in which it crosses 

 the gullet a second time and again decussates (d), passing into 

 the outer layer (e e), in which it crosses the gullet for the third 

 time, and forms at b the non-decussating bundle ; so that the 

 one extremity (so to speak) of the loop is above, on the one side 

 of the cesophagus, whUe the other extremity is heloiu and on the 



1, 1'. The two lines of decus- 

 sation. 



2,2'. Non-decussating bundles. 



3. Crossing of the fibres form- 

 ing the outer layer. 



4, 4', 4". Inner layers. 



5. Outer layers. 



