58 EDWARD C. DAY 



fluctuation might be different for the two conditions. Table 4 

 was consequently prepared to test this possibility out : consecu- 

 tive ventrad series are brought together in one column and 

 consecutive dorsad series in another and the ranges of fluctuation 

 placed beside them so that the extremes may be picked out at a 

 glance. 



The least fluctuation exhibited by normal animals are those in 

 graph 15^, where the variation in three consecutive series of 

 both ventrad and dorsad beats is a single beat, and in the dorsad 

 series of 16\ where it is also a single beat for two consecutive 

 series. But the same fluctuation in consecutive series occurs 

 likewise immediately after the nerves between ganglion and heart 

 have been severed, as in the ventrad set of 15^, and after recovery 

 from extirpation of the ganglion had occurred, as in the dorsad 

 series of 16"; in both cases the fluctuation between two consec- 

 utive series is but a single beat. 



The maximum fluctuations that occur in normal consecutive 

 series of ventrad beats are 12 for animal no. 15, 17 for animal 

 no. 16, and 2 for animal no. 18; and in normal consecutive 

 dorsad series they are 14, 3, and 3 beats for the same animals, 

 respectively. The maximum is much higher after some of the 

 performed operations: 24 beats in the dorsad set of 15 where the 

 nerves had been severed, 26 in the dorsad set of 18 after the 

 same operation, and 30 beats in the ventrad set of 18 where the 

 ganglion had been removed. In several instances no data were 

 obtained for consecutive series following operations, owing to 

 the interruption of the observations. 



The fluctuations in consecutive series after recovery had taken 

 place range from the minimum of one beat to 2, 3, 4, 5, and 9 

 beats as seen in graphs 18, 16, 15 and 18, respectively. 



It is evident from the foregoing that fluctuations both small 

 and large occur in sets of consecutive series whether ventrad or 

 dorsad, irrespective of whether the animal was in the normal 

 condition or recovered condition or in a state of injury. The 

 fact that greater fluctuations occur in the normal than the re- 

 covered condition might be interpreted as indicating a greater 

 sensitivity, the source of which could be attributed to the pres- 



