388 MANUAL OF HISTOLOGY. 



downward, until at about the middle of its course the striped 

 fibres entirely disappear, being replaced by continuous layers 

 of unstriped muscle-cells: 



The fibrous envelope consists of connective tissue and elastic 

 fibres, arranged so as to form a thin, peripheral, sheath-like 

 membrane. 



Blood-vessels and lymphatics are found in less abundance 

 in the oesophagus than -in the mouth and pharynx. The for- 

 mer are arranged in the shape of capillary networks in the 

 mucosa. The papillary loops, already mentioned, take their 

 origin from these reticula. The larger branches are found in 

 the submucosa. The lymphatics occur as plexuses; one is 

 situated superficially in the mucous membrane, and communi- 

 cates by capillary vessels, with a second larger one, placed in the 

 submucosa. The glands are said to have special lymphatics. 



Nerves. An elaborate account of the mode of distribution of 

 nerves in the oesophagus is given in Ranvier's " Lecons d'ana- 

 tomie generale," 1880, p. 366 et seq. The following brief sum- 

 mary gives the main points : Nervous filaments proceeding from 

 the pneumogastrics find their way to the striped muscles, where 

 they terminate in the well-known eminences ordinarily found in 

 that tissue. These terminal bodies are seen to be very numer- 

 ous, a fact which corresponds to the importance and complex- 

 ity of nervous action concerned in the process of deglutition. 

 The terminal distribution in the unstriped muscle presents no 

 striking peculiarity. Between the two layers of the muscle- 

 coat we find' an arrangement analogous to Auerbach's gangli- 

 onic plexus, but the ganglia and their nerve-cells are larger and 

 appear to be more numerous than in the intestine. The nerve- 

 fibres proceeding from the vagus are medullated ; those from 

 the ganglionic plexus belong of course to the non-medullated 

 variety. 



THE STOMACH. 



The serous covering of this organ has the same general 

 structure as all visceral peritoneum, being composed of a con- 

 nective-tissue membrane lined by flat endothelial cells. 



The muscvlar coat of the stomach is divisible into three 

 layers, composed of, 1, external longitudinal fibres ; 2, middle 

 circular ; and 3, internal oblique fibres. All of these belong 



