Volume 1
Lectures on the principles and practice of physic : delivered at King's College, London / by Sir Thomas Watson.
- Sir Thomas Watson, 1st Baronet
- Date:
- 1871
Licence: Public Domain Mark
Credit: Lectures on the principles and practice of physic : delivered at King's College, London / by Sir Thomas Watson. Source: Wellcome Collection.
Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.
77/936 page 57
![.IV.] MECHANICAL CONGESTION. seldom that this measure alone suffices; and sometimes it would be ultimately hurtful to adopt it. The state of the constitution may be such, that the disposition to local plethora would be increased by the loss of blood. Undue susceptibility and dis- ordered action of the nervous system are liable to be aggravated by bleeding; and in proportion as the nervous functions are irregularly performed, does the tendency to unequal distribution of blood in the capillary vessels augment. We have daily examples of this in hysterical young women. It is not, there- fore, the mere congestion that we have to consider; we must look deeper, for its cause. Leave in the finger a small thorn : the blood will be collected there in consequence of the abiding irritatiou, and will continue to collect in spite of depletion. But extract the thorn, and your remedial measure of taking away blood is at once successful. So it is also with internal congestions of blood—of which the exciting and sustaining cause is not always so well known. Contrasted, in some important particulars, with active con- gestion such as I have been describing, is that morbid fulness of the capillary vessels which arises when the return of the blood from them towards the heart through the veins, is impeded by some mechanical obstacle. With this mechanical congestion the veins are exclusively concerned. Congestion of this kind maybe strictly local. It may be con- fined to a single limb, when the principal venous trunk belong- ing to that limb is compressed, or otherwise diminished in size; and when no collateral and compensatory channels for the returning blood have been established. If there be disease of the liver, of such a nature as to prevent a free passage of the blood through that organ, congestion will ensue in all those parts of the capillary system from which the blood is conveyed by the veins that ultimately concur to form the vena portce. The force of gravity alone is sufficient to produce venous con- gestion, and consequently congestion of the capillaries, in parts of the body in which, under ordinary circumstances, the cir- culation through the veins is aided, instead of being opposed, by that force. If, for instance, the head be suffered to hang downwards for a certain time, we see the unequivocal signs of such congestion in the tumid condition and the purplish red colour of the lips, cheeks, eyelids, and ears. When an impedi- ment to the free transmission of blood exists in the heart itself, a tendency to stagnation is produced, first in the vente cav«, then in the smaller ramifications by which these veins are fed,](https://iiif.wellcomecollection.org/image/b2129253x_0001_0077.jp2/full/800%2C/0/default.jpg)
