relation between the nervous and sanguiferous systems. 437 
Without some such means it would be difficult to conceive 
how any organ should be influenced by every part of the 
nervous system. We cannot suppose that it receives nerves 
from every part of this system. Indeed we know, that no 
organ does so. The following seems to be the state of the 
question. We see some parts influenced by every part of 
the nervous system, others only by certain small parts of it. 
In the latter instances, we see nerves going from these small 
parts directly to the parts influenced. In the former instances, 
namely, where it is found that the part is influenced by all 
parts of the nervous system, we see no nerve going directly 
from any part of this system to the parts influenced ; but we 
see these parts receiving nerves from ganglia, to which nerves 
from every part of this system are sent. It is therefore evi- 
dent from direct experiment, that the nerves issuing from 
ganglia convey the influence of all the nerves which termi- 
nate in them, to the parts to which they send nerves ; and 
consequently that this is one use of the ganglia ; nor does 
there seem any reason to induce us to believe, that they have 
any other use. Thus it would appear, that the ganglia and 
nervous filaments connecting them, which have been called 
the great sympathetic nerve, are, if I may be allowed the ex- 
pression, a channel of nervous influence flowing from every 
part of the brain and spinal marrow, from which those organs 
are supplied, which are subjected to the influence of the 
whole nervous system ; those subjected to any particular 
part of this system, being supplied directly from that part. 
This view of the subject is consistent with the observations 
of anatomists, who remark that the great sympathetic has by 
no means the character of a nerve. Nothing surely can be 
