Scientific Proceedings (76). 



greed culture from October 8, 1914, to date, during which time it 

 has attained 951 generations. 



Bryn Mawr Race. Isolated at Bryn Mawr, Pa. In pedigreed 

 culture from January 7, 1915, to February 8, 1916, when it was dis- 

 continued at the 650th generation. 



Oxford Race. Isolated at Oxford, Ohio. Pedigreed culture 

 started on July 16, 1915, and has to-day (May 24, 1916) attained 

 the 779th generation. 



Woods Hole Race. Isolated at Woods Hole, Mass. Pedi- 

 greed culture begun on August 11, 191 5, and discontinued on 

 January 14, 1916, at the 305th generation. 



Each of the above races has shown endomixis at the regular 

 rhythmic periods throughout its culture and therefore this ad- 

 ditional data from races from diverse sources fully corroborates 

 the statement of Woodruff and Erdmann 1 that "this reorganiza- 

 tion process is a normal phenomenon and probably occurs in all 

 races of the species Paramaecium aurelia." 



90 (1154) 



Further investigations on the cyclic changes in the mammalian 



ovary. 2 



By Leo Loeb. 



[From the Department of Comparative Pathology, Washington 

 University, St. Louis, Mo.] 



In former investigations I have described cyclic changes in the 

 ovaries of the guinea pig which depend largely upon injurious 

 influences exerted upon the ovaries in the period directly pre- 



1 Woodruff and Erdmann, " Complete Periodic Nuclear Reorganization without 

 Cell Fusion in a Pedigreed Raceof Paramaecium," Proc. Soc.for Exper. Biology and 

 Med., Vol. n, 1914 (preliminary paper). Erdmann and Woodruff, " Vollstandige 

 periodische Erneuerung des Kernapparates ohne Zellverschmelzung bei reinlinigen 

 Paramaecien," Biol. Cenlr., Bd. 34, 1914 (preliminary paper). Woodruff and 

 Erdmann, "A Normal Periodic Reorganization Process without Cell Fusion in 

 Paramaecium," Journal of Exper. Zoology, Vol. 17, No. 4, 1914 (complete paper). 



1 During the summer 1915 serial sections of a number of ovaries were made for 

 me in the department of anatomy of Washington University. I wish to express my 

 appreciation to Dr. R. T. Terry for placing the facilities of his laboratory at my 

 disposal. 



