182 MAMMALIA. 



in every region of the body by modifying the functions of nerves with which it 

 combines. 



In the calf, the coarse structure is well calculated for showing the connexions 

 between the sympathetic and spinal nerves. The branches of the sympathetic can be 

 traced close to the anterior and posterior bundles of spinal nerves with which they 

 coalesce, but cannot be followed to the spinal cord without severing communicating 

 filaments. After general and careful observation, it must be determined that branches 

 proceed from the ganglia of the sympathetic to the spinal nerves, and become incor- 

 porated with them after separating into minute filaments. The texture of the 

 sympathetic itself is more fibrous, or open, in some parts of different animals, and the 

 ganglion may also appear in threads like a plexus, or be more close and solid, and 

 having a fleshy character. In the ass, the cervical and first thoracic ganglia are close 

 and the spinal open ; part of the semilunar is close, but not of so dense a texture as in 

 man. The other thoracic ganglia of the sympathetic, with the prolongation and the 

 first and second lumbar, correspond with the open texture of the ganglia of the dorsal 

 and the first and second lumbar nerves of the spine ; the third lumbar ganglion, both of 

 the sympathetic and spinal nerves, is less flat and open ; the rest of the lumbar ganglia 

 of each are more close and oval, but still of a loose texture. In the pig, all the ganglia 

 of the spinal nerves are close, but not so large, in proportion to the size of the nerves, 

 as in man ; all the ganglia of the sympathetic are close ; the semilunar is formed of a 

 delicate plexiform membrane, with some thin patches of close ganglion, and all the 

 plexuses for the abdominal viscera are very slender, until the termination of the aortic 

 in the large ganglion at the beginning of each hypogastric plexus. The spinal and 

 sympathetic ganglia may therefore be placed with those of simise, but the semilunar 

 below those of the ass. In the simise, hedgehog, jaguar, and dog, the spinal ganglia 

 are close, and each bundle becomes combined in one mass; all the ganglia of the 

 sympathetic are also close and membranous, and not open, as in many of those in the 

 calf and goat, and in a still greater degree in the ass. Some of the ganglia of the 

 sympathetic, which appear close, are not of a solid texture, like those in man, but are 

 formed of a denser congeries of fibres. 



