532 THE INTESTINAL CANAL, BY E. KLEIN AND E VERSON. 



of the oesophagus extend, according to Treitz,* into the external 

 fibrous membrane. The fibres of the muscularis externa of 

 the upper fourth of the oesophagus in Man are for the most 

 part transversely striated. But besides these, fasciculi of smooth 

 muscular fibres are met with sometimes running vertically ex- 

 ternal to the longitudinal muscular layer, at others running 

 circularly in the circular fibrous layer, and at others vertically 

 between the fibres of this latter layer. 



In the second fourth the smooth muscular fibres are so abun- 

 dant that they sometimes exceed those of the transversely 

 striated, predominating especially in the anterior wall amongst 

 the longitudinal, and in the posterior wall amongst the circular 

 layers of muscular tissue. 



The muscularis externa, in its lower half, is composed of 

 smooth fibres exclusively. Externally the muscular layers are 

 invested by a fibrous sheath composed of connective tissue and 

 elastic fibres, which for the most part run in a longitudinal 

 direction. 



At certain parts between the circular and longitudinal mus- 

 cular fibre layers the nerves form quite a continuous layer, 

 the branches of which perforate the circular muscular coat, in 

 order to reach the submucous tissue. Amongst the nerves 

 running between the circular and longitudinal layers ganglion 

 cells, partly isolated, partly enclosed in a nucleated capsule, are 

 found, as well as groups of ganglion cells united together by 

 means of their processes ; moreover, a few ganglion cells occur 

 in the smaller nerve trunks as they run through the mucous 

 membrane. Remakf has described true ganglia as being 

 situated on the cesophageal branches of the vagus. 



The lymphatics, according to TeichmannJ partly run in the 

 mucosa, partly in the submucous tissue, but do not form a dou- 

 ble capillary network as in the wider portions of the tube. 



In the oesophagus of the Dog the muscularis mucosae does not 



* Treitz, loc. cit. 



t Ueber peripherische Ganglien an den Nerven des menschlichen Nah- 

 rungsrohres, ' On the peripheric Ganglia situated upon the Nerves of the 

 Alimentary Tube in Man; " Miiller's Archiv, 1858, p. 189. 



I Teichmann, Das Saugader System, " The Lymphatic System," loc. cit. 



