368 
DR. PHILIP ON THE POWERS OF LIFE. 
parts secondarily affected in consequence of the power of sympathy, more or less in- 
fluences both systems, all parts being more or less supplied with nerves from both. 
But we have sufficient evidence in the phenomena of disease, compared with the 
results of the experiments referred to, that here, as in the instances just pointed 
out, the central organs of the sensitive, directly influence those of the vital system. 
A sympathetic pain it is well known referred to any part will at length produce 
actual inflammation of the part. Now while the pain alone exists, we know that the 
derangement, which produces it, is in the central organs alone of the sensitive system, 
and in no degree in the part to which it is referred ; and we also know from the facts 
which have been stated that there is no channel through which this derangement 
can influence either the nerves or vessels of the part, but through the central organs 
of the vital system. 
When the affection of the nerves or vessels of the part is the original disease, it 
influences the central organs of both systems by the actual disease of the part ; but in 
the former case there is no other channel of communication than that just referred to. 
The central organs of the sensitive, having no power over either the nerves or vessels., 
can only influence them through the central organs of the vital system. Thus arises a 
double bond of connexion between the two systems, the central organs of the sen- 
sitive system directly influencing those of the vital system, and the nerves of the 
sensitive system being necessarily influenced by all deviations from a state of health 
in whatever part, for all parts may be affected through the central organs of the vital 
system, the degree to which the effect in the sensitive system takes place being pro- 
portioned to that in which the part is supplied with nerves of sensation. As the 
central organs of the sensitive, directly influence those of the vital system; the latter, 
through the extremities of the different nerves with which the two sets of organs are 
associated, influence the former. Hence we have just seen the fatal obscurity of 
many diseases of those vital organs, which are ill supplied with this class of nerves ; 
and as the more chronic the disease, the less it disturbs the sensitive nerves, it is in 
the more chronic cases that the obscurity is greatest, and consequently attended with 
the greatest risk. 
Different parts of the central organs of the sensitive system correspond to different 
parts of the general frame. This is perhaps sufficiently proved by our being enabled 
by experience to refer our sensations to the seat of the cause which excites them ; 
but in many of the inferior animals, where both the brain and spinal marrow partake 
of the organs of the sensorial power, it may be proved by direct experiment, because 
after the removal of the brain we find the sensorial power lost only in those parts 
which derive their nerves from that organ. 
But how comes it that the central organs of the vital system also have relation to 
certain parts of the general frame, the nerves associated with these organs conveying, 
as appears from what has been said, their combined influence, which is bestowed 
alike on all vital organs ? 
