THE ALIMENTARY TRACT. 



291 



Isolated fold of mucous membrane of small intestine 

 of Rana lemjioraria ; after Langer. Forty times 

 natural size. Blood-vesseLs striped, lacteals shaded. 



lacteals are not simple but in the form o£ a coarse network (Fig. 

 189), (Langer).] 



(7) [The nerves of tlie Fig. 190. 



small intestine (p. 200) usu- 

 al ly follow the arteries to 

 the muscular coats, between 

 which they form a plexus 

 (Auerbach's plexus) ; from 

 this numerous twigs are 

 given off, which coiirse alone 

 or in company with vessels 

 to the mucous coat, where 

 a second plexus (Meissner^s 

 plexus) is formed. Auerbach's 

 plexiis, according to Klein, consists of bands of nervous fibrils in 

 endothelial sheaths ; they branch and inosculate, and thus form a 

 plexus. Where several such branches 

 meet, a more or less complicated decus- 

 sation of the bands of fibres takes place. 

 Along these nervous bands are ganglion 

 cells, either isolated or in groups. The 

 cells are large, generally spherical, and 

 contain a sharply outlined nucleus with 

 a single or double nucleolus. The 

 smaller cells generally appear to possess 

 only one process, which can be traced 

 from the protoplasm of the cell between 

 the fibrils of the nerve-trunk. The 

 larger cells are distinctly multipolar, 

 their protoplasm being provided with a 

 number of fine processes, or, as is 

 oftener the case, with one large and 

 several small processes. In many in- 

 stances Klein was able to distinguish 

 around the ganglion -cells a capsule of 

 a spherical or ovoid shape. In these 

 cases the body, as well as the processes 

 of the ganglion-cell, were lying within 

 the capsule. This system of ganglion- 

 cells is in connection with the individual 

 bimdles witliin the nerve-trunks. 



r 2 



C 



Transverse section of a fold of the 

 mucous ^lembrane of Rana Utnpo- 

 raria ; after Langer. Sixty times 

 natural size. 



A Lacteals with transverse trabe- 



culae. 

 B Circular muscular layer. 

 C I;ongitudinal muscular layer_ 



Blood-vessels striped. 



