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KINETIC HORMONES — I 



Fig. 3-1. Kymograph record of the heart beat of the crab, Cancer. 

 Changes in frequency are shown as abscissae in relation to the time 

 scale in minutes (below); changes in amplitude are shown as 

 ordinates. The record reads from left to right. The arrows indicate 

 the times at which different reagents reach the heart, which is the 



