KYMOGRAPHS. 



293 



Kymograph, is that used in all ordinary measurements and ex- 

 periments on blood pressure. In order to overcome the inertia 

 of the mercurial column, another instrument has been devised 

 which will be mentioned in speaking of the character of the curve 



FIG. 133. 



LUDWIG'S KYMOGRAPH with continuous paper. The instrument consists 

 of an iron table, above which the recording surface is slowly drawn past the 

 writing points from an endless roll of paper on the left by the motion of the 

 cylinder (c), and rolled up on a spindle next the driving-wheel on the right. 

 The mercurial manometers (D) are fixed so that the open ends come in front 

 of the firm roller upon which the paper rests. The writing style can be seen 

 rising from these tubes while the other limbs of the manometers lead through 

 the stop-cocks to the tubes which are in communication with the blood- 

 vessels. The time is recorded by means of a pen attached to the electro- 

 magnet (M), which, by a "breaking" clock, is demagnetized every second. 

 The moment at which a stimulus is applied is marked by a key to which 

 another pen is attached near the time-marker. 



(p. 297). When an experiment of long duration has to be made, 

 a recorder with a long rolled strip of paper can be employed 

 (Fig. 133). 



