THE 



AMERICAN NATURALIST 



Vol. XLIX February, 1915 No. 578 



CYCLES AND RHYTHMS AND THE PROBLEM 

 OF "IMMORTALITY" IN PARAMECIUM 



PKOFESSOR GARY N. CALKINS 

 Columbia University 



The recent brilliant work of Woodruff and Erdmann 

 has thrown a flash of light upon the old question of age 

 and death in protozoa and upon the problem of the sig- 

 nificance of conjugation. The long, successful cultivation 

 of Paramecium aurclia by Woodruff led Jennings to say: 



The work of Woodruff demonstrates that the very limited periods 

 wiihin which Maupas and Calkins observed degeneration has no signifi- 

 cance for the question as to whether degeneration is an inevitable 

 result of continued reproduction without conjugation. In other words, 

 it annihilates all the positive evidence for such degeneration, drawn 

 from work on the infusoria. It justifies the statement that the evidence 

 is in favor of the power of these organisms to live indefinitely, if they 

 are kept under' healthful conditions. It shows that Weismann was 

 correct in what he meant by speaking of the potential immortality of 

 these organisms. 1 



The same work of Woodruff led Minot to say in the 

 course of his German lectures : 



Quite conclusive as to the absence of senescence are the experiments 

 of L. L. Woodruff, who has maintained a pedigreed race of Para- 

 mecium for five years without conjugation. 2 

 Woodruff also makes the statement in different publica- 

 tions that the cells of his pedigreed race of Paramecium 



1<{ Age, Death and Conjugation in the Light of Work on Lower Organ- 

 isms," Pop. Sci. Mo., June, 1912, p. 568. 



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