ON THE GANGLIONS AND SYMPATHETIC NERVES. 509 



ments traverse them simply from one side to the other. The 

 pulpy substance of these ganglions is so Strongly united with 

 the medullary filaments, that it is very difficult to separate 

 them. This substance, besides, appears to differ from that of 

 the other ganglions: it is harder, more close, and more tena- 

 cious. This is especially remarkable in the cceliac ganglions 

 and in those of their plexuses. The membrane of the gan- 

 glions of this series is cellular and firm, but has not the fibrous 

 solidity of that of the spinal ganglions. 



806. The cords and the nervous branches, in a word, the 

 nerves which unite these ganglions, greatly differ from those 

 which are immediately derived from the spinal narrow. In- 

 stead of diminishing like these last, in proportion as they de- 

 part from their origin, or from their central extremity they 

 furnish successive divisions, we see them indifferently dimi- 

 nish or increase, or not change their size in departing from 

 the ganglions. The ganglionary nerves have less power of 

 cohesion and more fragility than the others. The external 

 envelope of the ganglions continues upon the nerves to a cer- 

 tain distance; beyond the point where this communication 

 ceases to be apparent, the neurilema appears thinner and more 

 intimately united with the medullary substance than in the 

 other nerves. Their internal substance results, like that of 

 the ganglions, from medullary filaments, and pulpy, gray and 

 reddish substance, that can be hardly separated from them; the 

 filaments, or the branches united to form a cord, are them- 

 selves hardly separable; the ganglionary nerves, finally, seem 

 to be formed of the same substances as the ganglions, these 

 being only elongated into cords. However, the nerves of 

 the ganglions are not all absolutely similar: those which unite 

 the spinal ganglions to those of the sympathetic nerve, and 

 the splanchnic nerves, which go from the thoracic ganglions 

 of the sympathetic to the coeliac ganglions, seem intermediate, 

 by their white colour, their cylindrical form, their fibrous 

 composition, their firmness and tenacity, between the nerves 

 of the spinal marrow and the reddish gray, flattened, irregu- 

 lar, pulpy ; soft and fragile nerves of the sympathetic. Scarpa 

 pretends that the sympathetic nerves may be anatyzed by 

 anatomy, aud reduced into filaments like the others. I think 



