540 THE SYMPATHETIC SYSTEM OF NERVES, BY DR. S. MAYER. 



trunks, and indiscriminately near their centre or their 

 border. 



The cells of the sympathetic system exhibit the essential 

 features of other nerve cells, such as have been described in 

 the third chapter of this work, but they present, in addition, 

 a few peculiarities which permit them to be distinguished from 

 the central cells of the cerebro-spinal organs. And just as the 

 nerve cells of different regions of the brain and spinal cord 

 differ in respect to their form, size, number of processes, shape, 

 and number of their nuclei, etc., so a different physiognomy 

 is presented by those of different parts of the sympathetic 

 system. 



Form. The most common forms presented by the sym- 

 pathetic nerve cells are oval, round, pear-shaped, or fusiform. 

 Bidder has described cells from the caeliac ganglion with rect- 

 angular borders, which appear like cubes arranged in longitu- 

 dinal rows. I have frequently met with similarly formed cells 

 in the sympathetic of the Frog. 



Size. In any cluster of ganglion cells collected into a gan- 

 glion, the cells are found to exhibit extraordinary differences 

 in their size, so that one cell may be four times as large as 

 another with which it is in contact. It was formerly admitted 



Fig. 262. 



Fig. 262. Three quadrate and linearly arranged cells. 



on insufficient evidence, that the sympathetic nerve cells were, 

 on the average, of smaller size than those of the nerve centres ; 

 the incorrectness of this statement may, however, readily be 

 demonstrated, as there is no difficulty in isolating cells of the 

 largest calibre from the sympathetic ganglia. The cells 

 appear to be of semi-solid consistence, but to possess a certain 

 amount of elasticity, since after their form has been altered by 

 pressure or other mechanical agency, they immediately resume 

 their original shape on its removal. 



With our present means of examination we are able to 

 distinguish, in the sympathetic nerve cells, a sheath, a proper 



