TISSUES OF THE BODY. 



335 



Fig. 320. Sketch of a mammalian sympathetic 

 ganglion, a, 6, c, nervous trunks^ d, multi- 

 polar cells; rf*, some of the latter with a divid- 

 ing nerve fibre; e, unipolar, and/, apolar cells. 



to one another, in the first place, apolar ganglion cells (/) are to be met 

 with, but whether their number is a large one or no, we are unable to 

 determine. Secondly, unipolar cells 

 (e) are encountered, giving off a deli- 

 cate nerve fibre, which is distributed 

 peripherally. Again, we meet with 

 bipolar ganglion corpuscles, whose 

 two nerve tubes take a course at 

 one time opposed to each other, at 

 another in the same direction. It 

 is one of the many things also for 

 which we are indebted to Remak, 

 that he has pointed out besides, the 

 existence in the sympathetic of a 

 fourth form among these elements, 

 namely, the multipolar cell. Taking 

 their rise from the latter (d), we see 

 from three to twelve processes which, 

 by rapid ramification, may soon in- 

 crease threefold (d*). The amount 

 of these is dependent on the number 

 of nervous trunks in connection 

 with the sympathetic knot, and into 

 which the processes are continued in 

 the form of nerve tubes : thus it is greater in the solar plexus than in the 

 ganglia of other parts of the cord. 



According to the observer just mentioned, the processes of unipolar and 

 bipolar cells of sympathetic ganglia undergo division likewise. 



189. 



Beside these larger ganglia just described, we have to consider a multi- 

 tude of smaller, and also most minute nervous knots, which have only 

 recently been recognised, owing to their frequently microscopical dimen- 

 sions. We find them, on the one hand, containing numerous ganglion 

 corpuscles, or, again, with but few of the latter. Their number is quite 

 surprising throughout the body. They seem to belong, more or less, to 

 the sympathetic system, supplying principally the smooth and involuntary 

 muscles with their fibres. 



Among these may be numbered groups of ganglion cells, which are 

 found in the ciliary muscle of the eye, on the branches of the circular 

 plexus to be found in the same (C. Krause, H. Muller). Several small twigs 

 from the ciliary nerves, likewise penetrating into the choroid coat, form 

 there, in the deeper portions of the latter, a delicate plexus, in which 

 scattered ganglion cells and small aggregations of the same have been 

 remarked (H. Muller and Schweigger, Samish). 



Other small nervous knots were discovered also, many years ago, by 

 Remak on the branches of the N. glossopharyngeus, distributed to the 

 pharnyx and tongue ; but those on the twigs of the Lingualis, supplying 

 the last-named organ, are still more minute. The nervous twigs, likewise 

 distributed to the walls of the larynx and bronchi, as well as the interior 

 of the lungs, bear also similar ganglia upon them. 



Another series of extraordinary ganglia is to be met with in the muscle 

 of the heart, presenting itself in man and the mammalia imbedded in the sub- 



