SYMPATHETIC SYSTEM OF NERVES. 373 
of ganglia (c, fig. 191), that seem to belong to the same 
The nerves proceeding from this system, which is called the 
_ Sympathetic, are distributed, not like those of the cerebro- 
_ spinal, to the skin and muscles, but to the organs of digestion 
and secretion, and to the heart and blood-vessels. Hence the 
former system of nerves, being that by which sensations are 
received and spontaneous motions executed, is called the 
nervous system of animal life ; whilst the latter, being con- 
. nected with the nutritive processes alone, is termed the nervous 
system of organic life. M 
462. What is the nature of the influence which the Sym 
thetic system exerts over the functions of the parts to which 
it is distributed, is not yet clearly made out. The sympathetic 
nerves distributed to the alimentary canal have been ascer- 
tained to have the power of exciting its peristaltic actions ; 
and those which are distributed with the blood-vessels (on the 
_ coats of which they form a minute net-work) have a direct influ- 
| ence over their calibre, producing changes in the local circulation 
in obedience to passions and emotions of the mind, as well as 
to states of other bodily organs. Of this influence we have a 
_ familiar example in the acts of blushing and turning pale from 
_ agitation of the feelings, and a more decided but less frequent 
ene in the fainting which sometimes occurs from a sudden 
shock. It is doubtful, however, whether the Sympathetic 
system really possesses motor filaments of its own ; its motor 
_actions being certainly in part dependent upon filaments de- 
rived from the cerebro-spinal system. The action of its motor 
fibres upon the muscular coats of the blood-vessels supplying 
the glands, serves to regulate the quantity of the fluids secreted 
“by these organs, especially in cases in which the demand for 
‘the secretion is intermittent; but as there is evidence that 
‘that in virtue of the two modes of action just explained, it 
‘BS to harmonise and blend together the various actions of 
Nutrition, Secretion, &c., in such a manner as to bring them 
ito conformity with each other, and with the condition of 
he organs of Animal life. 
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