230 ON THE EARLY STAGES OF INFLAMMATION 
and the corpuscles moving on at slight intervals with no tendency to adhere, 
on a drop of chloroform being applied, I saw the very same corpuscles instantly 
become checked in their progress by sticking to each other and to the capillary 
walls, and move on slowly in masses with considerable intervals. Thus the 
nature of the effect produced upon the red corpuscles of the blood when chloro- 
form is applied to the web is the same as that caused by mustard, viz. an abnor- 
mal degree of adhesiveness ; whereas the earliest evidence of the direct action 
of chloroform on blood out of the body is the loss of the adhesive property of 
the red discs, as has been mentioned in Section I.1. That the effect on the blood 
within the vessels of a part inflamed by chloroform is secondary to a change 
in the tissues is further proved by the circumstance, that abnormal accumulation 
of slowly moving corpuscles may last for hours together without stagnation, 
as a consequence of the application of this irritant for an extremely brief period.’ 
Long after all the blood which could possibly have been directly acted on by 
the chloroform has left the vessels, successive fresh portions continue to experi- 
ence precisely similar changes in passing through the irritated area. 
Heat produces similar effects. If the foot of a frog which is under the 
influence of chloroform be covered entirely with wet lint, except a small area of 
one of the webs, and a red-hot cautery iron be held for a few seconds about 
half an inch above the exposed part, inflammation will be excited in the area 
in proportion to the time of the action of the dry heat upon it ; but on removal 
of the lint, the circulation will be found perfectly healthy in the surrounding 
parts. In the severer cases stagnation is universal in the exposed area, and 
the epidermis becomes eventually raised by the exudation of serum beneath it ; 
but in milder instances nothing more than accumulation of slowly moving 
corpuscles is produced, and I have observed this state of the part to continue 
for hours after the heat was applied. Here again the effect on the blood was 
obviously not due to the direct action of the heat upon it, but to some changes 
which it had effected in the tissues of the part on which it had acted. 
Evidence of the same kind, but still more conclusive, is derived from the 
effects of mechanical irritation, where the agency is free from all objection of 
possible chemical action on the blood. The method adopted was that of com- 
pressing a small part of the middle of the web between little pads of soft material 
attached to the ends of the blades of a pair of surgical dressing forceps, by which 
* SE€ Pp. 215. 
* The gradual supervention of the effects of irritation upon the blood may be watched very con- 
veniently by arranging a piece of lint soaked in chloroform, so that the vapour may play upon the web 
while the eye of the observer is over the microscope. If the chloroform be removed when the tendency 
to accumulation of corpuscles exists in a very slight degree, restoration to health will occur within a few 
minutes. 
