52 EDWARD C. DAY 



for the series is not only a striking contrast to the 78 beats of the 

 preceding graph, but also to the 38 beats for the normal uninjured 

 condition exhibited by the first graph of the set, 18-; the number, 

 instead of progressing from 78 to about 85 or 90 pari passu with 

 the increase in rate from 49 to 44 seconds for the initial 10 beats, 

 has fallen way below the normal. 



Since the amputation of the siphon entailed considerable loss 

 of blood, this abrupt shortening of the series by decrease in num- 

 ber of beats must in some way be correlated with that loss. It 

 is conceivable that the length of a pulsation series may be influ- 

 enced by different factors, of which one is blood pressure, 

 another the exhaustion of anabolic materials, a third the accumu- 

 lation of the products of catabolism, and a fourth nerve reflexes, 

 but to which one is to be attributed the diminished number of 

 beats cannot at this point be taken up for discussion. 



The fact to be emphasized, however, in connection with this 

 particular operation is, that the rate of beat has gone on increas- 

 ing according to expectation, whereas the number of beats and 

 the length of the series has not. 



RECOVERY FROM OPERATIONS 



The day following the extirpation of the ganglion the animals 

 exhibited a heart-beat which was quite normal in every respect. 

 The pulsation-series had shortened, the rate of beat had slowed 

 down, the intervening pauses had lengthened again, and the 

 strong acceleration which had cropped out in the longer series as 

 a result of injury had disappeared except for the same faint trace 

 characteristic of the normal beat. 



A comparison of the recovered condition in graph 15^, table 1, 

 with the initial normal condition in graph 15^ reveals precisely 

 the same number of beats in the ventrad series of both, namely 

 25, in contrast to 83 beats for the state of injury resulting from 

 removal of the nerve ganglion; and in the dorsad series 28 and 23 

 beats for recovery and normal in contrast to 54 beats for the 

 state of injury. For the recovered condition the rate of the 

 ventrad series runs 51, 51, 27 as compared to 55, 55, 29 for the 

 normal condition, and both the recovered and the normal condi- 



