no Journal of Comparative Neurology. 



of the frog, which was in connection with the spiral process of 

 these cells. Ehrlich's observations were soon confirmed by 

 Retzius (72), Smirnow (73) and Arnstein. About the same 

 time Aronson {6j) described and pictured peri-cellular plexuses 

 in methylen-blue stained ganglia of the rabbit — superior cervi- 

 cal, coeliac and cardiac. They were then described by Sala 

 (23), Van Gehuchten (21) and Lenhossek (24) in Golgi prepar- 

 ations of the sympathetic ganglia of mammalia, and in more 

 recent years by Dogiel (25) and Kolliker (34) and a number of 

 other investigators. The peri-cellular plexuses or baskets 

 have thus been found in the various ganglia of the chain, in the 

 prevertebral and terminal ganglia. 



They are, as will be shown, always intra-capsular, in direct 

 contact with the cell bodies of the sympathetic neurons, within 

 the capsule of which they are found ; and are therefore not to 

 be confused with the peri-celhilar nests described by Cajal, which, 

 as will be remembered, are extra-capsular. 



In giving a fuller description of these structures as found 

 in the various vertebrates, I shall take up first the mammalia, 

 then birds, reptiles, amphibia and fishes in the order named. 



(a) Mammalia. The peri-cellular baskets, about the sympa- 

 thetic cells of mammalia, vary greatly in complexity, even in the 

 same ganglion. A typical one may be described as follows, 

 a section of a sympathetic ganglion of a cat or dog, stained 

 in methylen-blue and counter-stained in alum carmine serving 

 for purpose of description. In such preparations the cell 

 bodies of the sympathetic neurons are stained a pale red, the 

 axis-cylinders and baskets are alone stained blue. In such 

 preparations it may be seen that one, two, three or even more, 

 small varicose nerve fibers approach a ganglion cell and before 

 or after piercing the capsule, they break up into a number of 

 smaller branches, which in turn may or may not undergo fur- 

 ther division and then anastomose or interlace to form a plexus 

 around the cell body of the ganglion cell in question. It seems 

 to me that the complexity and the arrangement of the fibrillae 

 in the network constituting the so-called peri-cellular baskets 

 are largely accidental and not to be looked upon as showing 



