Compensatory Regulation. II 



:i process which begins at the distal end and is usually accom- 

 panied by a loss of vitality with the approach of general bodily 

 decay. In Series V, where all five arms were removed, none of 

 the specimens retained its full vitality for the whole 46 days, 

 though one did so for 33 days. 



A glance at the table (Table I) is sufficient to show both of the 

 main points brought out in the general statement of the results. 

 In the first place the rate of regeneration of the arms is greatest in 

 medium-sized individuals, decreasing for both the smaller and the 

 larger ones and second, the rate of regeneration is dependent on the 

 number of arms removed. Excepting Series V, where all the 

 arms are removed, there is an evident increase in the rate of regen- 

 eration of the arms as we pass from the cases with the fewer to 

 the cases with the greater number of removed arms. 



As both these factors enter into the individual measurements 

 the proper relations can best be represented graphically by means 

 of "curves." Such "curves" are shown in Figs. 2 and 3 and the 

 relative rates of regeneration of the arms are also represented for 

 two typical individuals in Fig. 4, which gives two specimens, one 

 from Series I (one arm removed) and the other from Series IV 

 (four arms removed). In each of the individuals in Fig. 4 the 

 condition of the arms 46 days after the operation is represented. 

 Each of the four removed arms of the individual from Series IV 

 has evidently regenerated more rapidly than the single removed 

 arm of the individual from Series I. 



In Fig. 2, Series I and IV, with respectively one and four 

 arms removed, are compared. The individual cases are shown 

 by dots. The abscissae give the sizes of the animals as represented 

 by the disk diameters in millimeters. The ordinates give the 

 lengths of the regenerating arms also in millimeters. In the series 

 where more than one arm was operated on the regeneration length 

 as given is an average of all the regenerating arms of the individual. 

 The individual cases of each series are connected by lines so as to 

 give a basis for comparison of the two groups. The unbroken 

 lines represent the lengths of the members of Series I and the 

 dotted lines those of the members of Series IV. The upper two 

 curves give the measurements as taken 22 days after the operation, 

 the middle pair those at 33 days and the lower pair those at 46 

 days. In each group the curve showing the rate of regeneration 

 of the arms in the series with four arms removed is well above the 



