No. 578] 



CYCLES AND RHYTHMS 



75 



justified in saying that throughout the seven years Wood- 

 ruff's Paramecium has undergone the equivalent of con- 

 jugation on the average once each month, and if it is 

 equivalent to conjugation, then his long culture of more 

 than 4500 generations has no bearing on the question of 

 old age and natural death in Paramecium. 



Nothing in this work of Woodruff and Erdmann seems 

 more clearly and forcibly demonstrated than that the cycle, 

 this "phantom" of many investigators, resolves itself 

 into a demonstrated fact, and that Woodruff's "rhythm" 

 and Calkins 's 1 'cycle ' ' are but different names for the same 

 phenomenon. If natural death is a necessary end to jus- 

 tify our use of the term "cycle," we may ask the perti- 

 nent question : WTiat happened to those individuals which 

 did not undergo asexual endomixis in Woodruff's long 

 culture? If they died, does not this fact indicate the end 

 of a cycle? If they underwent parthenogenesis, the 

 equivalent of conjugation, does not this fact indicate the 

 beginnings of new cycles? If they continued to live with- 

 out reorganization, evidence for which has never been 

 given by Woodruff, then there would be some justification 

 for our authors' conclusion. To argue that it is the same 

 race which continues after asexual endomixis is to use 

 the same argument that Weismann used unsuccessfully, 

 viz., that an ex-conjugant is the same old individual since 

 no corpse has been formed and therefore the infusoria 

 are immortal. 



The frequent statement made by Woodruff that his 

 long culture sustains the view that old age and need of 

 conjugation are not necessary attributes of living matter 

 are contradicted by these later results. For example, he 

 states in 1913 : 



