AUTOMATISM OF PERIPHERAL GANGLIA. 677 



of other parts of the head) on cutting centrally of the ganglion stellatum than 

 on cutting peripherally of it, and on cutting centrally of the inferior cervical 

 ganglion than on cutting peripherally of it. They found, also, a greater dila- 

 tation of the vessels of the foot of the dog on cutting the sympathetic chain 

 centrally, than on cutting it peripherally, of the second and third lumbar 

 ganglia. Hence they concluded that these ganglia exercise a tonic action 

 on the parts mentioned. The considerations which lead me to consider the 

 experiments inconclusive are given ahove (p. 675). 



According to Francois-Franck, 1 section in the dog of the ciliary nerves con- 

 taining constrictor fibres for the sphincter iridis, causes greater dilatation of the 

 pupil than section of the third nerves. 



2. The second method has not given any certain results as regards the 

 superior cervical ganglion, and it is on this that experiments have been 

 chiefly made. 



Bernard 2 stated that excision of the superior cervical ganglion 

 gives greater and more permanent paralytic effects than section of the 

 cervical sympathetic. It is not, however, clear that Bernard excised a 

 sufficiently long portion of the nerve to prevent regeneration, or, indeed, 

 did more than state a general impression. Schiff, 3 Callenfels, 4 and Pye- 

 Smith 5 found no difference between the result of the two operations. 



3. Callenfels made three experiments upon rabbits by the third method, 

 i.e. he cut the cervical sympathetic on one side and excised the superior 

 cervical ganglion on the other. In two cases he found the temperature of 

 the ear higher on the side on which the nerve only was cut ; in one case the 

 temperature was lower on this side. Tuwim, 6 in similar experiments in rabbits, 

 found no difference in the flushing of the ear on the two sides ; nor in similar 

 experiments in frogs did he find any difference in the flushing of the two sides 

 of the tongue. 



Jegorow, 7 however, states that, in a series of experiments on the dog, the 

 dilatation of the pupil was markedly greater after excision of the ciliary 

 ganglion than after section of the third nerve a little centrally of the ciliary 

 ganglion. 



On the whole, the evidence at present leads us to conclude that 

 autonomic ganglia, after separation from the central nervous system, do 

 not exercise any considerable tonic action on unstriated muscle, but 

 that it is possible they have a slight action. 



Apart from tonic action, it is not improbable that peripheral nerve 

 cells, severed from the central nervous system, may at times stimulate 

 the tissues to which they send fibres. The nerve cells and fibres remain 

 responsive to chemical and mechanical stimuli, and it is not unlikely 

 that substances circulating in the blood and the movements of the body 

 now and then serve as stimuli to the local nervous mechanism, and so 

 set in action the peripheral apparatus. 



So far, we have considered nerve cells which normally exercise a 

 tonic influence on the tissues with which they are in connection. Of 

 the others, there is little that need be said here. There is some evidence 

 that the submaxillary ganglion passes into a state of slight tonic 

 activity after section of the chorda tympani, for, so far as the experi- 



1 Trav. clu lab. clc Marry, 1880, tome iv. 



- Op, tit., supra, [). 657. :: Op. tit., supra, p. 657. 



4 Op. til., supra, p. 657. ■' Op. ait., supra, p. 657. 



8 Arch. f. d. ges. Physio/., Bonn, 1881, Bd. xxiv. S. 115; cf. also Budge, ap. tit., 

 1885, S. 125. 



7 Arch, slaves tie biol., Paris, 1887, tome iii. p. 322. 



