HE author's interest in the measurement of intra-visceral ,pressure started wi!th the notion that She results of uretero-'colic anastomosis might be par.tly dependent upon pressure within the colon. Preliminary investigation, utilising an electrical pressure transducer, gave support to this hyp~)thesis in so far as it showed that not only was ~here marked variation between the iatra=eolonic pressure of ir/dividuals, but a!lso that these variations correlated with the state of renal function, following transplantation of ,the ureVers, Daniel (1961). Belief in the importance of these obse~wations led to an endeavour to find a simple m~t'hod of measuring intra-colonic pressure, with the hope t har such measuremen,ts might become part of Vhe routine associated with operations for :diversion of 'the urinary stream. Pioneer studies vf t~he motor physiology Of the gastro-intes~inal tract were based upon measurements made by baltoon-kymographs, Pflunger (1887), Hurst (1911) and Cannon and Washburn (1912), but during the last two decades such ap,para~u's has been superseded by the system of electrical recording introduced by Brody and Quigley (1947) and even more recently, radio-telemetry has been used. However, the modern electrical and wireless methods, as well as the older .balloon methods, require expensive apparatus not normally found outside specialised research departments, while the simple meVhod to be described below uses ap~par~tus which can very quickly be assembled from m~terials available in virtually any hospital. Furth'ermore, ~this method is applicable to a wide range o~f physiological studies of wthich two only will be consi~dered in Vhis article, namely, measu.remer~t of pressure within the sigmoid colon and measurement of pressure and flow within the common bile ,duct.