EARLY STAGES Ol' INFLAMMATION. 
1 49 
agents, showed that the corpuscles, both red and white, were 
obstructed in their progress through the irritated part, in 
consequence of their tending to adhere in an abnormal de- 
gree to one another and to the walls of the vessels. The 
effects upon the blood were always similar, although the 
means employed to produce irritation were exceedingly 
various, such as solutions of salts, mustard, essential oils, 
chloroform, heat, galvanic shock, mechanical violence, etc. 
The irritant was generally so applied as to act only upon 
a small area of one of the webs, and it was found that the 
abnormal adhesiveness of the blood-corpuscles was in the 
first instance always precisely limited to the spot which had 
been thus acted on, though it frequently extended afterwards 
more or less to surrounding parts. At the same time the 
vessels of the irritated spot did not differ materially in calibre 
from those in its vicinity which participated in the arterial 
dilatation induced by the stimulus. The exact correspon- 
dence between the extent of the irritant application, and 
that of the effect upon the blood, showed that the latter 
must be due to direct action either upon the blood itself or 
the tissues of the web. That it was not the result of direct 
action upon the blood was evident from the two following 
considerations. In the first place, most of the agents em- 
ployed to cause irritation, when applied to freshly drawn 
blood, either had no effect upon the corpuscles, or destroyed 
instead of increasing their adhesiveness. Secondly, if em- 
ployed so as to act mildly on the web, they induced an ab- 
normal condition of the blood, short of actual stagnation, 
though very apparent, namely, slow movement of numerous 
and adhesive corpuscles ; and this state of things might 
last, although the time of operation of the irritant was often 
limited to a few T seconds, or even a still briefer period. Long 
after all the blood which could possibly have been directly 
acted on had left the vessels of the part, successive fresh 
portions continued to experience precisely similar changes 
in passing through the irritated area. Hence the author 
considers the conclusion to be inevitable, “ that the tissues 
as distinguished from changes of calibre in the blood-vessels, 
are the primary seat of inflammation, and that the effects on 
the blood are secondary results of such derangement.” 
The remarkable fact discovered by Dr. H. Weber, of 
Giessen, but observed independently by the author, that ac- 
cumulation of corpuscles occurs in the vessels of a part 
irritated, after circulation has been arrested by a tight liga- 
ture round the thigh, furnished the opportunity for careful 
comparison between the conditions of blood in healthy and 
