DYNAMICS OF MORPHOGENESIS 169 



these results will be presented in full at another time: at pres- 

 ent only the results of a comparison between animals stimulated 

 mechanically to motor activity and those left undisturbed will be 

 considered. For experiments of this sort KCN is far more satis- 

 factory than alcohol or other anesthetics since it does not inhibit 

 motor activity so rapidly and so completely as do they. Thus 

 far only the direct method has been used in experiments of this 

 kind, for the indirect method would require frequent stimulation 

 of the worms during weeks, while with the direct method this is 

 necessary only for an hour or two. 



Series 515. Two lots of ten worms each from the same stock 

 and of the same size (18 to 20 mm. in length) were placed in 500 

 cc. Erlenmeyer flasks in KCN 0.001 m. Lot 1 was left undis- 

 turbed in diffuse daylight and the worms soon came to rest and 

 remained almost wholly quiet until death. Lot 2 was shaken 

 every five to ten minutes during two hours and the worms were 

 dislodged by currents of water from a large pipette. In order to 

 do this it was of course necessary to uncork the flask, so that 

 some loss of KCN may have occurred in this case, but as table 2 

 shows an}' such loss certainly did not interfere with the result. 

 The worms were examined every half-hour, but in the table only 

 the figures for hour intervals are given. 



It is evident from the table that Lot 2, the stimulated worms, 

 begin to disintegrate before Lot 1 and continue in advance of it 

 during the whole course of the experiment. The difference is not 

 extreme but is sufficienth'' large to leave no doubt of its existence. 

 Two of the worms of Lot 2 live as long as any of the worms in 

 Lot 1 , but the average length of life in Lot 2 is distinctly less than 

 in Lot 1 . The alternate readings omitted from the table show the 

 same relation in every case. 



That stimulation and motor activity increase the average rate 

 of reaction, there can be no doubt and we see that the worms with 

 the higher rate die first in the KCN. The only question which 

 can be raised concerning these results is as to the possibility of 

 fatigue in the stimulated lot and consequently a lower rate of 

 reaction. This possibility can undoubtedly be excluded, for I 

 have at various times attempted to produce fatigue by repeated 



THE JOURXAL OF EXPERIMENTAL ZOOLOGY, VOL. 14, NO. 2 



