A NORMAL PERIODIC REORGANIZATION PROCESS 

 WITHOUT CELL FUSION IN PARAMAECIUM 



LORANDE LOSS WOODRUFF AND RHODA ERDMANN 



Osborn Zoological Laboratory, Yale University 



SIXTY-SIX FIGURES (FOUR DOUBLE COLORED PLATES) 



CONTENTS 



I . Introduction 425 



II. Material and methods 432 



A. Method of conduction of main Culture 1 432 



B. Method of conduction of Subculture IE 434 



III. Description of the cytological changes in the reorganization process. 436 



A. Descending phase 436 



1. Macronucleus 437 



2. Micronucleus 440 



B. Climax 443 



C. Ascending phase 450 



IV. Cytological details of series of pedigreed cells in the reorganization 



process 457 



A. Series of cells from Line VI. 458 



B. Series of cells from Lines I to V 46& 



V. The reorganization process in this race after conjugation, and in other 



races and species of Paramaecium 473 



VI. The reorganization process and its relation to rhythms 476 



VII. The reorganization process and its relation to depression periods 481 



VIII. Endomixis and its relation to conjugation 489^ 



IX. Endomixis and its relation to parthenogenesis 492 



X. Endomixis and its relations to variation, heredity and the significance 



of conjugation 494 



Literature cited 498 



Explanation of plates 503 



I. INTRODUCTION 



The conception of the Protozoa as primitive animals has led 

 to innumerable studies on these forms — morphologists and phy- 

 siologists alike being animated with the idea that here many 

 of the riddles of life propounded by the so-called higher animals 

 would be presented in a simple form and so be more readily 

 solved. While this view of the Protozoa is undoubtedly true 



425 



THE JOl.R.VAr. OF EXPERIMENTAL ZOOLOGY, VOL. 17, NO. 4 

 NOVEMBER, 1914 



