62 



Scientific Proceedings (97). 



steps to be taken, before attempting to decide, if conjugation has 

 an effect and which particular effect in Paramecia. All authors 

 till now have studied the combined influences of unrecorded occur- 

 rences of endomixis and influences of recorded occurrence of con- 

 jugation. The intermictic period of 28 days duration alternates 

 with the endomictic phase indefinitely. The climax, when the 

 most important steps of the reorganization process take place, 

 lasts one or two days, while the ascending and descending phases 

 of the endomictic period overlap either with the first days or last 

 days of the intermictic period. The number of daily divisions 

 amounts to one or two, hence approximately 50 in one intermictic 

 period, which we have divided for convenience into three sub- 

 periods. Changes effected by the constantly occurring divisions 

 and by the approaching of the next endomixis go parallel and can 

 not be considered separately. 



By our culture methods we can create a constant environment, 

 by previous observations we can recognize how a culture changes 

 in mean length and mean breadth, standard deviation and corre- 

 lation between length and breadth before, in and after division. 

 We eliminate further by our methods all animals while dividing 

 or in constriction and then we are able to recognize periodical 

 regular combinations of the four quantities in question in each 

 intermictic subperiod. In the second subperiod the animals 

 reach their mean length, have a medium to high standard devia- 

 tion and correlation; in the third subperiod they do not reach 

 their mean length, but have a very high standard deviation and 

 correlation. In glancing over the changes in the quantities 

 shortly after or in division, we know that the four quantities in 

 question change too in value, i. e., the standard deviation is low 

 immediately after division, and high shortly before division. 

 Therefore in each intermictic period the values of the four quan- 

 tities are in the whole measurements either balanced, augmented 

 or diminished. We find that a culture shortly before the onset 

 of the next endomixis is distinguished by a low division rate, a 

 low mean length, a high mean breadth, a high standard deviation 

 and high coefficient of correlation. In Line I the standard 

 deviation passes through the following values during the inter- 

 mictic period, Line I 553O10 with 2.424 -f . 105, Line I 553O14 with 



