426 NERVOUS SYSTEM. 



distinct nucleolus. They present a nucleated capsule, prob- 

 ably composed of connective tissue, which is sometimes lined 

 on its inner surface with a single layer of flattened, polygo- 

 nal epithelium. Some of the cells are unipolar, some are 

 bipolar, and some are multipolar. In frogs, Beale and Ar- 

 nold have described a peculiar appearance in certain cells, 

 there being a single, straight prolongation, surrounded by a 

 fine, spiral fibre. These have not been demonstrated in the 

 human subject, and it is not necessary to enter into a discus- 

 sion of the probable origin and nature of the spiral fibre. 1 

 The connection between the cells and fibres of the sympa- 

 thetic is probably the same as in the cerebro-spinal centres, 

 and is represented in the accompanying diagram, taken from 

 Leydig. 



FIG. 11. 



Sympathetic ganglion with multipolar cells ; highly magnified. (LEYDIG, Traite ffhistologie, 

 Paris, 1866, p. 193.) 



General Properties of the Sympathetic Ganglia and Nerves. 



The older writers had no definite ideas with regard to the 

 functions of the sympathetic system, and were divided, even, 

 on the simple question of its sensibility, some assuming that 



1 For a full account of the spiral fibres and the peculiarities of structure of 

 the sympathetic system, the reader is referred to the elaborate article by Mayer. 

 (STRICKER, Handbuch der Lehre von den Geweben, Leipzig, 1871, S. 815.) 



