iQis] Lorande Loss Woodruff 377 



At the present stage of our knowledge, the rhythm may perhaps ' 

 be considered as an expression of a sort of temporary " senescence," 

 for which is provided an internal, automatically working, antidote in 

 the form of endomixis. But, if one considers this as a "senes- 

 cence "-phenomenon and endomixis a " rejuvenation "-phenomenon, 

 then it is equally pemiissible so to consider the momentary fluctuat- 

 ing periods of anaboHc and catabolic ascendency in the metab- 

 oHsm of the cell. But I would point out that it is a case of trying 

 to f orce new wine into old bottles in order to save an idea, and that 

 this line of reasoning, pushed a little farther, approaches perilously 

 near a reductio ad absurdum. One certainly must grant that the 

 prevalent idea of "senescence " in infusoria is far removed from this 

 subtle, automatically eliminated type which rhythms may indicate. 

 The work at Yale in the past has been to determine whether con- 

 jugation is a necessary factor in the life of infusoria; and we believe 

 that 5250 generations without conjugation is strong evidence in the 

 negative. But, obviously, because conjugation is not necessary in 

 the life of Paramcocium under favorable environmental conditions, 

 it does not follow that conjugation is not necessary under other 

 conditions, or that it does not have a "rejuvenating" function. 

 There is nothing mutually exclusive in the fact that conjugation is 

 not necessary and the idea that conjugation has a dynamic function 

 when it occurs. In fact we have ahmys leaned toward and defi- 

 nitely stated the view that conjugation probably has a dynamic 

 function, which is important when the organisms are subjected to 

 unfavorable conditions. Calkins has secured some evidence which 

 indicates that, after conjugation, all the processes of the cell includ- 

 ing reproduction proceed with greater vigor ; and thus he substan- 

 tiates the view of Bütschli, Maupas, Hertwig, and others. Jen- 

 nings, on the other band, definitely states that there is no evidence 

 from his work that conjugation in the infusoria increases the repro- 

 ductive power of, or rejuvenates, the organism physiologically in 

 any way and puts all the emphasis on the side of Variation and 



heredity. 



However, since the cytological phenomena of conjugation, with 

 the exception of syncaryon f ormation, are so similar in their broad 

 features with those of endomixis, and since accelerated vital activities 



