CENTRAL FUNCTIONS OF PERIPHERAL NERVE CELLS 583 



Once the temporary effects of the operation had passed off, the animals 

 exhibited the following phenomena. All the cross-striated muscles of the pos- 

 terior parts degenerated and became transformed into connective tissue. The 

 external sphincter of the anus alone withstood this degeneration, remaining com- 

 pletely functional as long as the animal lived. The digestive processes went on 

 in regular fashion, just as in the normal dog. The urine was normal and was 

 normally voided. A pregnant female gave birth to five whelps; one of the 

 young, permitted to suckle, grew rapidly, the milk being perfectly normal. No 

 secretion of sweat could be clearly made out. The blood vessels of the posterior 

 parts recovered their tonus and remained capable of reacting to a local con- 

 strictor or dilator stimulus. But vascular changes in distant parts of the skin 

 could not be induced nor could alterations in the intestinal movements, nor 

 movements of the sphincter ani nor of the bladder be induced by stimulation 

 of the hind paws. Shedding of the hair took place in fairly normal fashion, 

 but terminated earlier on the fore parts which were still in connection with the 

 central system than on the hind parts. The bones took on a peculiar rotten 

 character. When the external temperature was not too low, the heat regulation 

 was carried on with adequate precision. 



It should be mentioned also that certain poisons, like anagyrin (from Ana- 

 gyris fcetida, Gley), as well as certain substances obtainable from various organs 

 of the body (extract of the kidneys and adrenals cf. page 366), can pro- 

 duce a considerable vasoconstriction even when the entire nervous system is 

 destroyed. 



These and other analogous phenomena show beyond a doubt that many 

 functions of the body can be carried on independently of the central nervous 

 system. It is probable, though not absolutely proved, that they take place 

 with the help of nerve cells present in the peripheral ganglia. There remains, 

 of course, a possibility that these organs act often quite automatically. 



But there are some statements in the literature which show that reflexes 

 can be mediated through the sympathetic ganglia, although they teach us 

 nothing as to the significance which these reflexes may have in the normal 

 processes of the body. 



Roschansky destroyed the spinal cord of the cat below the cervical region 

 and then stimulated the central end of the splanchnic, whereupon the blood 

 pressure rose several millimeters of Hg. The rise in pressure did not appear 

 when the sympathetic chain was sectioned between the ninth and tenth ganglia ; 

 hence it was reflexly produced through sympathetic ganglia as a center. 



Langley also has observed reflexes from sympathetic ganglia and has given 

 an explanation of their peculiar mechanism. After section of all the branches 

 connecting the inferior mesenteric ganglion with the central nervous system 

 (cf. page 392), contractions of the bladder and of the external anal sphincter, 

 vasoconstrictions in the lower parts of the rectal mucosa and in the mucosa of 

 the uterus on the opposite side can be obtained (best in the cat) by electrical or 

 mechanical stimulation of the central end of one hypogastric nerve. These effects 

 are dependent upon nerve cells in the ganglion itself, for they fail to appear 

 after nicotine is applied to that ganglion. But they are not reflexes in the usual 

 sense of the word, for by means of the degeneration method it has been shown 

 that the nerve fibers carrying the excitation to the ganglion have their trophic 

 center neither in the ganglion nor peripheral thereto, nor yet in the spinal 

 ganglion. They are therefore efferent nerves. 



