ORGANS OF THE BODY. 



403 



Externally this submucous plexus is connected with the remarkable 

 and no less developed plexus myentericus of Auerbach. The latter, with 

 its regularly flattened ramifications, but more minute ganglia, is situated 

 between the internal transverse and external longitudinal muscular tunic 

 of the gut. These it supplies 

 with its numerous twigs, 

 forming first a secondary 

 plexus of threads, O'OOl- 

 0-005 mm. in thickness, each 

 of which possesses from 3 

 to 6 of the finest nervous 

 filaments (L. Gerlach), leav- 

 ing no doubt as to the motor 

 nature of the latter, although 

 we are still in the dark as to 

 the ultimate termination of 

 the fibres. 



We may form some esti- 

 mate of the extent to which 

 the nervous system of the in- 

 testines is developed, from the 

 fact that about 100 ganglia, 

 belonging to the submucous, 

 and over 2000 to the my en- 

 teric plexus, are to be found 

 in 1 Q" of the intestine of the rabbit. 



The following is the general arrangement of the vessels of the intestine. 



On arriving in the walls of the latter, a few small twigs are given off 



Fig. 487. A ganglion from the submncous tissue of a 

 human infant, a, nervous knot; b, radiating twigs; c, 

 capillary network. 



Fig. 488. From the small intestine of the Guinea-pig, a, plfows n>yentericv&, with its 

 ganglia ; b, c, fine, and ef, larger lymphatic vessels. 



to the serous covering of the part, after which the vessels break up in the 

 muscular tunics into the usual well-known capillary network with elongated 



