A manual of the practice of medicine / by George Hilaro Barlow.
- George Hilaro Barlow
- Date:
- 1861
Licence: Public Domain Mark
Credit: A manual of the practice of medicine / by George Hilaro Barlow. Source: Wellcome Collection.
Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.
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![observed ; they become enlarged and distended,* the blood also passmg through them with increased velocity ; at -the same time that new vessels appear to be produced, most probably from those which before did not allow of the passage of the red coipuscles, or which admitted them in a quantity insufficient to render their colom- apparent, now permitting them, to enter freely; the globules also manifest a tendency to cohere into irregular masses, which sometimes pass througli the capil- laries, and may be observed in the veins. This is active congestion, or the sthenic hyperaamia of Andral. This state of things cannot, iiowever, continue long without leading to further change ; if it have not been intense, the in- creased, quantity of blood, and rapidity of its movement may gradually subside, and the vessels return to then- original con- dition ; or it may pass into inflammation, to be described here- after, or it may be relieved by effusion of the whole blood giving rise to hjEmorrhage, or of the liquor sanguinis, as in fibrinous dropsy, or of serum, as in serous dropsy, or it may pass into the next form of congestion. (2.) This form of congestion is spoken of, by autliors in this country, under the name of ]passive congestion, and by Andral and the French pathologists as asthenic, or ^mssive liypermmia, in which the capillaries become distended with blood, and the motion of that fluid impeded. Passive congestion may also occur, without any previous acceleration of blood in the arteries or capillaries, of which we may often see instances when the lower or dependmg parts of aged or debilitated subjects become livid or piuple; the contractility of the capillaries not being suiiicient, as in liealth, to overcome tlie distending force arising from the gravitation of the blood. It also succeeds to active congestion, the increased energy of conti-actility in the small vessels being followed by a correspondmg deficiency, so that, becoming dilated under the force of the active congestion they have not sufficient contractility to resume their original size, but remain permanently distended with blood. (3.) Allusion has been made to impediments in the course of the circulation, causing accumulation of the blood which is foUowirig the obstructed portion, or, as it is termed, tergal to it. Tins form of congestion, which is called mechanical, exists exclusively, iu the first instance, in the veins, though it may be propagated from them to the capillaries:—it is instanced by the eflects of compression upon the venous trunks of an extremity ;—by obstruction to the passage of the blood throuo-h tiie right side of the heart, which gives rise to venous conges- tion of the whole system, by opposing the return of the blood * Alison's Pathology, p. 99.](https://iiif.wellcomecollection.org/image/b21509104_0045.jp2/full/800%2C/0/default.jpg)
