XXIII.--The popliteal artery. When any circumstance renders it necessary to tie this vessel in preference to the femoral, the ligature should be placed above its upper pair of articular branches; for by so doing a freer collateral circulation will take place in reference to the leg. The ligature in this situation will lie between the anastomotic and articular arteries, which freely communicate with each other. XXIV.--The anterior and posterior tibial and peronoeal arteries. As these vessels correspond to the arteries of the forearm, the observations which apply to the one set apply also to the other. [Footnote] [Footnote: For a complete history of the general vascular system, see The Anatomy of the Arteries of the Human Body, by Richard Quain, F.R.S., &c., in which work, besides the results of the author's own great experience and original observations, will be found those of Haller's, Scarpa's, Tiedemann's, &c., systematically arranged with a view to operative surgery.] THE END.