ON THE EARLY STAGES OF INFLAMMATION 22% 
the degree of pressure could be regulated at will. The results of this treatment 
were identical with those of heat, as just described. If the pressure was not 
made too severe, no mechanical obstruction was produced in the vessels, which 
nevertheless became loaded with slowly moving or stagnant corpuscles ; and 
on one occasion I observed the capillaries of an area which had been pinched, 
still transmitting languid streams of blood containing great excess of corpuscles 
several days after the injury had been inflicted, while in the surrounding parts 
the circulation continued perfectly healthy. Mechanical violence, like heat, 
chloroform, and mustard, had effected an alteration in the tissues on which it 
operated, in consequence of which the blood in their vicinity assumed abnormal 
characters ; and many other facts of similar nature might be added, if necessary, 
to show that this is the course always followed when accumulation of corpuscles 
in the vessels is induced by the action of irritants. 
In discussions regarding the causes of the phenomena of inflammation seen 
in the frog’s web, the great difficulty has hitherto been to account for the puzzling 
fact, that while the arteries still retain that state of enlarged calibre which is 
best adapted for easy transmission of the blood, its accelerated movement comes 
to give place to unnatural retardation and ultimate stagnation. Accordingly, 
various theories, mechanical, chemical, and vital, have been proposed? to explain 
the transition from ‘ determination of blood’, as the condition of dilatation 
of the arteries with increased flow through the capillaries has been termed, to 
inflammatory congestion, as the accumulation of corpuscles in the vessels may 
perhaps be most fitly designated. But the second simple experiment with 
mustard, to which I would again direct the attention of the reader, proves in 
a very beautiful manner that these two results of irritation are totally distinct 
in nature and independent in cause. The dilatation of the arteries, it will be 
remembered, affected not only the part on which the mustard lay, but also all 
the rest of the web, showing that it was developed indirectly through the medium 
of the nervous system; whereas the accumulation of the blood-corpuscles in 
the vessels below the mustard was, as we have seen, the result of the direct 
action of the irritant upon the tissues. The arterial dilatation in the web 
generally led to no changes in the quality of the blood, which, though the experi- 
ment was continued for some hours, retained to the last its natural characters, 
just as would have been the case had the enlargement of the vessels depended 
on an operation performed upon the spinal cord. The accumulation of cor- 
1 See Pathology and Practice of Medicine, by W. P. Alison, M.D., F.R.S.E. ; Principles of Medicine, 
by C. J. B. Williams, M.D., F.R.S.; Lectures on Surgical Pathology, by James Paget, F.R.S. ; ‘ Observations 
on the State of the Blood and the Blood-vessels in Inflammation,’ by T. Wharton Jones, F.R.S.: Guy's 
Hospital Reports, vol. viii; Clinical Lectures, by J. H. Bennett, M.D., F.R.S.E.; also Professor Henle, 
as quoted by Wharton Jones, op. cit. 
