AN IMPROVED MERCURY MANOMETER.
C. C. GUTHRIE, S.B., M.D.(From the Hull Physiological Laboratory, University of Chicago.)CHICAGO.The accompanying figure illustrates the main features of a mercury manometer which I have found more convenient than the ordinary type for blood - pressure work.The float A and cap B are made of aluminum and the piston C and the guide rod D of polished or nickel-plated steel. The wood base is cut out in such a manner as to protect the ends of the tubes E and F. E is connected with a three-way canula, which is in communication with the pressure bottle and blood vessel. In filling or washing out the manometer from the pressure bottle with the solution used to prevent clotting (I employ 2 per cent. sodium citrate), F, which is fused into the manometer tube E, about 1 cm. above the level of the mercury at