242 EXPERIMENTAL PHYSIOLOGY. 



A. (a.) Arrange the recording apparatus for a continuous 

 tracing. The clock-work is wound up, and the drum is so 

 adjusted, that, when it moves, it unwinds the continuous 

 white paper from a brass bobbin placed near it. Arrange 

 a time-marker connected with a clock, provided with an 

 electric interrupter, to mark seconds at the lower part of the 

 paper. It is usual to use a pen-writer charged with a 

 solution of aniline to which a little glycerin is added to 

 make it flow freely. 



(6.) Partially fill the manometer with dry clean mercury, 

 and in the open limb of the manometer place the float, 

 provided with a pen or sable brush moistened with aniline 

 ink containing a little glycerin. See that the float rests 

 on the convex surface of the mercury. 



(c.) The closed or proximal side of the manometer at 

 its upper part is like a T-tube, the stem of which is 

 connected by thick india-rubber tubing to a piece of 

 flexible lead tubing, on the free end of the latter is tied a 

 glass cannula of considerable size, and over the india-rubber 

 tubing connecting the cannula with the lead tube is placed 

 a clamp. The proximal end of the manometer is filled 

 by means of a pipette with a saturated solution of sodic 

 carbonate as high as the stem of the T-piece. To it is 

 attached a long india-rubber tube, which is connected with 

 a pressure-bottle filled with a saturated solution of sodic 

 carbonate, and kept in position by a cord passing over a 

 pulley fixed in the roof. A clamp compresses the india- 

 rubber tube just above the manometer. Open this clamp 

 and also the one at the end of the lead pipe. The alkaline 

 solution fills the whole system, and after it does so, and no 

 air- bubbles are present, close the clamp at the end of the 

 lead tube, and then the one on the pressure-bottle tube. 

 It is well to have an inch or more of positive pressure in 

 the manometer. See that the writing-style writes smoothly 

 on the paper, and that it is kept in contact with the latter 

 by a silk thread with a shot attached to its lower end. 



B. To Insert the Cannula. (a.) Arrange the necessary 

 instruments in order on a tray. Scissors, scalpels, forceps 

 {coarse and fine), seeker, well waxed ligatures, small aneur- 

 ism needle, bull-dog forceps, cannulse, sponges. 



