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ON THE EARLY STAGES OF INFLAMMATION 273 
the disorder, as when an inflamed foot is kept in a dependent posture. Sup- 
posing this to be the whole mechanism of the disease, its origin would be suffi- 
ciently intelligible ; for we have seen that vascular dilatation caused by irritation 
operating through the medium of the nervous system appears to depend on 
a depressing influence produced by excessive action of the afferent nerves upon 
the ganglia which preside over the arterial contractions. There are, however, 
some circumstances, such as the dryness of the nostril which may exist in the 
early stages of coryza, and sudden suppression of urine in consequence of 
urethral irritation in cases where renal congestion becomes ultimately estab- 
lished, which seem to indicate that other functions as well as arterial contraction 
may be primarily arrested by nervous agency in the early stages of inflammation. 
The study of the pigmentary system of the frog has afforded proof that other 
tissues besides muscular fibre are under the control of the nerves, and it seems 
not unlikely that gland-cells or other forms of tissue may, like nerve-cells, be 
reduced to a state of inactivity by excessive nervous action ; and thus we seem 
to have a clue to comprehending what at first appears anomalous, that prostra- 
tion of the vital energies of the part actually inflamed may be brought about by 
unusually great activity in the parts of the nervous system specially concerned 
with it. This, however, is a wide subject, which requires further investigation. 
But in the mean time we may, I think, consider as satisfactorily established the 
fundamental principle, that whenever inflammatory congestion, or, in other 
words, that disturbance of the circulation which is truly characteristic of inflam- 
mation, exists in any degree, the tissues of the affected part have experienced 
to a proportionate extent a temporary impairment of functional activity or 
vital energy. 
LISTER 1 Al 
