94 



THE NERVOUS SYSTEM 



FIG. 48 



VPP 



LCP 



uterus and the heart). The cells of these various nuclei connect directly 

 by contact with the medullated, white neuraxones of cells seated prob- 

 ably in the lateral horn of the spinal cord or in the homologous region 



of the brain (Hiiber). The 

 cells of the gangliated cord 

 (but not those of the preverte- 

 bral ganglia) send outward 

 fibers (known as those of 

 Remak) which are "gray," 

 i. #., non-medulla ted. These 

 are distributed exclusively 

 to smooth muscle-fibers and 

 perhaps to epithelium all over 

 the body by way of the spinal 

 nerve-trunks. The branches 

 to the spinal nerves and be- 

 yond are the so-called gray 

 rami communicantes, while 

 the fibers arising in the gan- 

 gliated cord above referred 

 to are the white rami. The 

 latter are found only from the 

 dorsal and first one or two 

 lumbar spinal nerves, but the 

 gray rami extend to each of 

 the spinal nerves, each gang- 

 lion sending inward axones 

 to two or three of them. The 

 prevertebral ganglia send non- 

 medullated fibers to the vis- 

 cera of the thorax and the 

 abdomen, continuing, doubt- 

 less more or less altered, the 

 messages they receive from 

 the gray matter of the cord 

 or from the small much- 

 branched cells of the gan- 

 glia of the gangliated cord. 

 The peripheral ganglia in 

 similar manner retail to the 

 tissues in which they are 

 situated the motor (and se- 



Diagram of the sympathetic. (Flower.) Cretory ?) influence they re- 



ceive from the cord's gray 



matter direct, from the ganglia of the gangliated cord, or from the pre- 

 vertebral ganglia. DogiePs recent work on the heart-action well illus- 

 trates the work of these peripheral ganglia. 



GsD 



