FIG. 18. Tracing from the dog in anaphylactic shock. From 

 above downward the tracings are: myocardiograph, blood- 

 pressure, base line, membrane manometer, base line, signal, time 

 in seconds. The down strokes of the myocardiograph tracing 

 represent cardiac contractions. The perpendicular line was 

 drawn arbitrarily through the blood-pressure curve at the point 

 where the fall began. Corresponding points in the myocardio- 

 graph and Hurthle manometer tracings were measured and are 

 indicated by the cross where the recording levers were not in 

 accurate alignment. (From Eisenbrey and Pearce. A study of the 

 action of the heart in anaphylactic shock in the dog, Journal of 

 Pharmacology and Experimental Therapeutics, 4, 21. 1912.) 



