532 OPEEATIOXS ON THE CIRCULATOKY SYSTEM. 



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

 and the possibihty of gangi-ene. The vakie 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 wound by pricking. 



(b) Jlediate 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 betvpeen the injvu'ed ves- 

 sel and the compressing apparatus. It may take effect either 

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

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

 sels, principally arteries which, 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 which temporary and 

 permanent hemostasia can be obtained is the same, excepting that 

 the cords, bandages and tourniquet are replaced by graded com- 

 presses, supported by rollers or appropriate bandages, which are 

 continued only dui'ing the existing necessity. 



The objection to this hemostatic method, and which it shares 

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

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

 necessary, other tissues, with other vessels, veins and nerves alike, 

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

 turbances of varying degrees of sevei'ity will occm- in parts situ- 

 ated beyond the comijressed 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 cany it toward the center, in passing over the wound 

 akeady 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 minimum time 

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

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

 be especially influenced by the consideration whether the cahbre 

 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 obliterated, one or two 

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



