WEST OF ENGLAND VETERINARY MEDICAL ASSOCIATION. 57 
Healthy condition of the part itself is altered, the change being 
one more or less of degeneration, from impaired nutrition, succeeded 
by the effusion of inflammatory products into the elemental structures 
and intervening interstices. 
Phenomena. —In congestion the quantity of blood is increased, 
but the rate of its motion is lessened. In determination we have 
everything augmented ; there is an increased size of the vessels, and 
an increased quantity of blood within them, circulating through 
them with increased velocity. In inflammation we have a combina¬ 
tion of these conditions ; we have an increased size of the vessels, 
an increase in the quantity and rapidity of the motion of the blood, 
but conjoined with this we have a tendency to its arrest, to its stag¬ 
nation at points. In studying tlie phenomena of inflammation in 
the web of the frog’s foot under the microscope, w^e observe that the 
first change on the application of a stimulus, is the momentary 
contraction followed by dilatation of the artery ; the flow of blood 
through it and the capillaries is at first accelerated; retardation 
from congestion then ensues; and, lastly, stagnation at points. 
At these centres of commencing stagnation it will be seen that 
the blood appears to ebb and flow, oscillating to and fro, and then 
stopping at last; the immediate stagnation taking place in those 
capillaries which are not in the direct line of passage from an artery 
into a vein, and the arrest taking place by the red corpuscles 
coalescing by mutual adhesion into masses, which, after being car¬ 
ried bodily up and down more and more slowly, at last appear to 
block up the vessel, partly by overcrowding and distending it, and 
partly by becoming adherent to its walls, this adhesion usually 
commencing at the angle of union between two capillaries. Around 
the stagnant part the vessels are crowded by an aggregation of the 
red corpuscles, which appear to be more closely packed in conse¬ 
quence of the draining away of the liquor sanguinis. The blood 
does not enter the part of the vessel in which stagnation has taken 
place, but passes off by a collateral branch (Wharton Jones). 
At this part, also, where the circulation is retarded, the white cor¬ 
puscles may be seen to be increased in quantity, and appear to be 
adherent to the wall of the vessel, along which they are either 
stationary, or, at most, roll but languidly. Around the whole of 
this area, in the centre of which there is stagnation, with retardation 
of the blood, there is that increased rush of an increased quantity 
of blood characteristic of determination. 
The researches of Mr. Lister on the pigmentary system of the 
frog’s web have shown that in inflammation the tissues of the part 
which he regards as the primary seat of the affection are in a state 
of diminished functional activity; indeed, that the tissues of an in¬ 
flamed part approximate to the condition of dead matter, “or, in 
other words, have suffered a diminution of power to discharge tne 
offices peculiar to them as components of the healthy animal 
frame.” 
These are the general phenomena presented by an inflamed part, 
5 
LXII, 
