632 OPEEATIONS ON THE CIEOULATOBT SYSTEM. 



tained by ligatures and dressings, such as the division of the skin 

 and the possibility of gangrene. The value of this measure of 

 digital compression may be estimated by the fact of its successful 

 application to a vessel of the dimensions of the carotid artery in 

 a case of a vround by pricking. 



(b) Mediate Lateral Compression. — The compression here is 

 applied outside of the solution of continuity, in such a manner as 

 to leave a certain thickness of the tissues betvs^een the injured ves- 

 sel and the compressing apparatus. It may take effect either 

 directly upon the wound itself, or elsevehere along the course of 

 the vessel. It can be effectively made only upon superficial ves- 

 sels, princijjaUy arteries vchich, like those of the extremities, lie 

 upon or near enough to resisting surfaces to furnish a means of 

 support to the pressure. The manner in vs^hich temporary and 

 permanent hemostasia can be obtained is the same, excepting that 

 the cords, bandages and tom-niquet are replaced by graded com- 

 presses, supported by rollers or appropriate bandages, vrhich are 

 continued only during the existing necessity. 



The objection to this hemostatic method, and vrhich it shares 

 "with all the other processes of compression, is, that when a large 

 vessel is to be compressed, and a certain amount of force becomes 

 necessary, other tissues, vsdth other vessels, veins and nerves ahke, 

 must participate in the same pressure, and, as a consequence, dis- 

 turbances of varying degrees of severity will occur in parts situ- 

 ated beyond the compressed surface, proportioned to the duration 

 of their exposure to the acting cause. Hence the indication, in 

 applying the apparatus, to begin at the peripheric portion of the 

 region, to carry it toward the center, in passing over the wound 

 already protected and covered by the balls, pads or compresses, 

 which constitute the true means of compression. 



The principal objections to this process of hemostasia can be 

 obviated by leaving on the apparatus only for the miTiimnTn time 

 necessary to obtain the cicatrization of the wound of the vessel, 

 which wiU, of course, vary according to circumstances, and will 

 be especially influenced by the consideration whether the calibre 

 of the vessel is to be preserved or obliterated. 



If the vessel be a small one, the wound of small dimensions, and 

 the continuity of the channel is to be preserved, a few hours will 

 be sufficient ; or, if otherwise, it is to be obHterated, one or two 

 days will be required, or even at times one or two weeks. 



