TRANSLATIONS FROM CONTINENTAL JOURNALS. 285 
may exist at the same time with local hyperhaemia. The 
vascular spasm of the skin from the effects of cold—rigors— 
tends to anaemia, and the blood being thus thrown on the 
internal organs, produces in them a sort of plethora; and if 
the circulation is not speedily re-established,local congestions, 
more or less extensive, are the result. These positions de¬ 
monstrate that the superabundance of the blood in the capil¬ 
laries of an organ does not give a complete idea of conges¬ 
tion or active hyperhaemia; at least it does not give the 
difference between active and passive congestion. To esta¬ 
blish a definition so as to justify this morbid state, other 
elements must be taken into consideration. The first ques¬ 
tion is—what is there active in this congestion ? The con¬ 
tractile fibres do not actually dilate the blood-vessels. The 
blood is precipitated onwards, and this acceleration is caused 
by enlarging of the artery, produced by the atony of its 
parietes. In all this the defect in the resistance offered is 
manifest. From these facts active congestion is a pheno¬ 
menon characterised by the accumulation of the blood, its 
acceleration into some organ being caused by a disproportion 
between the resistance of the arterial parietes and the lateral 
pressure of this fluid. The causes are: 1st. a > Obstacles to 
the free flow of the blood, as from partial spasm; compres¬ 
sion ; c, from foreign bodies in the blood circulating with it, 
these being of too great bulk for the capillaries, and which 
are consequently obstructed by them, such as the agglome¬ 
rated corpuscles of purulent matter. In these cases the cir¬ 
culation is increased in activity in the collateral branches 
from the impulse given to it. 
2dly. The non-resistance of the vascular parietes, which 
yield to the normal pressure of the blood. Softening, or 
fatty degeneration, will cause the loss of elasticity and con¬ 
tractility, when a slight acceleration of the circulation will 
produce not only a dilatation, but sometimes a rupture of 
the vascular parietes. Internal haemorrhages have generally 
for their cause a want of integrity in the tunics of the blood¬ 
vessels. 
3dly. The atony of the vascular system, caused by the 
excitation of the sensitive nerves, producing paralysis of the 
vaso-motor nerves. This condition comprehends a large 
category of irritating causes, internal as well as external. 
(To be continued .) 
