400 DEFENCE OF THE DOCTRINE OF VITAL AFFINITY. 
any contractile organ by which it is propelled into those parts,—the most copious 
effusions sometimes taking place when the impulse of the blood, passing along 
the larger arteries, is distinctly feebler than natural during the whole disease; 
thus we can understand how the blood passing through an inflamed part should 
undergo a change in its own constituents, and how the fiuid, which escapes from 
the vessels there, should possess a peculiar composition, and be peculiarly fitted 
for certain vital actions, and thereby for repairing some of the injuries resulting 
from the inflammation itself. Thus, also, we can understand and admit a prin- 
ciple which has been confidently disputed, but which I have long thought, and 
now find to be maintained, as fairly established, viz., that matter exuding as a re- 
sult of simple inflammation, may afterwards degenerate, according to the state of 
the constitution, into various forms of heterologous deposit. (See e.g. Copland and 
Quain, in Medico-Chirurgical Transactions, vol. xxxiii., p. 144.) Still more, if we 
regard it, as I think we may, as an established fact, that the vital properties of 
living fluids, as well as solids, are of temporary duration only, and are subject 
to the general law, of increased action being followed by diminished action, or 
accelerated loss of vitality, we can understand how the most important con- 
sequences of inflammation, both beneficial and injurious, should be produced,—how 
the matter that was concerned in it being peculiarly excited, and, therefore, 
quickly rendered ete, should be peculiarly liable to Absorption, which we know 
to be the agent by which its injurious effects are chiefly effaced,—how the 
increased absorption should, under certain circumstances, extending to the ad- 
joining sound parts, effect that destruction of texture which we call Ulceration ; 
and how, in other circumstances, either of peculiar violence of the inflammation, 
or depressed vitality of the organ inflamed, this form of diseased action should, 
by the established laws of vitality, lead to premature death of the diseased 
part, i. ¢., either to partial Sloughing or more extensive Gangrene. All these 
are facts of the highest practical importance, of which we have explanations so 
far satisfactory, on the strict principles of induction, when we look to the changes 
that take place in inflamed parts in those living actions which I have referred to 
the heads of Vital Attractions and Repulsions, and Vital Affinities ; but I will ven- 
ture to say, that we never shall have any explanation of them consistent with the 
supposition, that the contractions of living solids are the only changes in organic 
life which are truly vital, 7. ¢., dependent on laws essentially distinct from those 
that regulate the changes of inorganic matter. 
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