ON THE eAKLY STAGES OF INFLAMMATION 269 
invest the mucous membrane of the mouth, the cilia with which they are pro- 
vided furnish the opportunity of which we have availed ourselves, of observing 
the stage of suspension of function in consequence of very gentle treatment ; 
and though the epidermis does not admit of this, it shows the further stage of 
loss of vitality by exfoliating after an amount of injury from which the imme- 
diately subjacent tissues readily recover. John Hunter was unquestionably 
correct in the opinion that the elevation of the cuticle in vesication depends 
not only on the effusion of serum beneath it, but on a primary separation arising 
‘from a degree of weakness approaching to a kind of death in the connexion 
between the cuticle and cutis’ For I find that in an amputated limb free 
from blood, although no effusion of serum can occur, the epidermis becomes 
speedily loosened in a part to which an irritant is applied, as for example, in 
a web treated with oil of turpentine, whereas it remains elsewhere firmly attached 
for days if the weather be cool. 
The temporary abolition of the normal relations between the blood and the 
tissues in inflammatory congestion,” must be added to the list of instances of 
suspension of vital properties by irritation. The tissues the healthy state of 
which seems most likely to be essential to that of the vital fluid, are those con- 
tiguous to it, viz. the walls of the blood-vessels ; and that these are really 
deprived of their vital endowments during inflammation, seems implied by the 
character of the material which is transmitted through them in that condition. 
For we have seen that the vascular parietes differ, in the state of health, from 
all ordinary solids in being destitute of any attraction for the fibrine, if not 
positively repelling it,? and that this is probably the cause of the merely serous 
character of the effusion which takes place in mechanical dropsy depending 
upon abnormal pressure of the blood within healthy vessels. On the other hand, 
the exudation of the liquor sanguinis in its integrity, such as occurs in severe 
inflammation, cannot, I think, be satisfactorily explained by the mere abnormal 
pressure of the blood produced by dilatation of the arteries and concomitant 
obstruction in the capillaries ; but seems naturally accounted for on the hypo- 
thesis that the walls of the vessels, like other tissues, lose, for the time, in inflam- 
mation, their vital properties, and, acquiring an attraction for the fibrine like 
that exercised by ordinary solids, permit it to pass without opposition through 
their porous parietes. 
It may be well to present a brief summary of the principal results arrived 
at in the present section. 
It appears that the various physical and chemical agents which, when 
1 Works of John Hunter, Palmer’s edition, vol. 111, p. 340. 
* See close of last section. * Vide antea, p. 241. 
