WOUNDS. 416 



haemorrliage results from oblique imperfect division of 

 the arterial coats. Arterial haemorrliage differs from 

 venous, in that the blood is pumped out in jerks and of a 

 bright scarlet colour, and the flow is promptly lessened by- 

 pressure on the course of the artery of supply to the injured 

 part. Venous hasmorrhage depends upon wounds of various 

 kinds, but these are less important in their effects than 

 those of arteries, on account of the smaller pressure in the 

 veins, whence haemorrhage is less difficult to control, and 

 also the blood which escapes being impure, its loss is less 

 felt by the system. 



When an artery has been partially divided complete 

 division generally suffices to check haemorrhage. In 

 other cases pressure will prove useful. This is applied 

 along the course of the artery between the heart and the 

 seat of injury ; torsion also is a very useful means, as it 

 places the coats of the vessel on the stretch in a spiral 

 manner, until they give way, and the jagged edges thus 

 produced recoil, and plug up the orifice of the vessel (see 

 figs. 35, 36, p. 222). LigaUires must sometimes be tried, 

 and tied with sufficient force to rupture the middle and inner 

 coats of the artery, for these retracting will lessen the lia- 

 bility to secondary haemorrhage when the ligature separates. 

 Application of the Actual Cautery to a bleeding wound 

 is a rough but effectual method, and in our patients, less 

 under supervision than human beings, is specially called 

 for when it is necessary to leave the patient to himself 

 after the operation. Hsemostatic agents administered in- 

 ternally (such as tannic and gallic acids) are seldom re- 

 quired. Styptics, as the chloride of iron and various 

 caustics, are sometimes very useful. Cold water is, per- 

 haps, the best of these agents. Yenous haemorrhage may 

 be generally restrained by pressure over the wound, or 

 by compression of the veins of supply. Usually it ceases 

 spontaneously. 



Bleeding having been checked all foreign bodies must 

 he removed. This is a matter of difficulty in some cases 

 of punctured wound, and it must be remembered that not 

 only bodies actually foreign, but pieces of dead tissue 



