EFFECT OF CONJUGATION 327 



For further comparison, I placed beside these, ten hnes derived 

 from a culture of this same series that had conjugated June 3, 

 and had lived in small mass cultures since. These belong to 

 the line K, figure 2. 



As this experiment gives the only results obtained that could 

 be interpreted as showing a favorable influence of conjugation 

 on survival and reproduction, it appears best to give in some 

 detail the records for the lines of propagation. This is done in 

 table 32, in the AppendLx. 



To understand table 32, the following must be considered: 

 Each line of any of the three sets was started with a single indi- 

 vidual August 11. The animals were changed to new fluid 

 every day or every other day (all being alike), and all those that 

 had been produced were retained, save on certain days, when the 

 number was reduced, by removal of certain of the animals. To 

 give the essential facts in the history of the cultures, it is there- 

 fore necessary only to give the number of individuals on these 

 dates, before and after reduction. This is what is done in table 32. 

 Thus, in line 1 of set K, the single individual of August 10 had on 

 August 14 produced 6, of which 4 were removed, leaving 2. On 

 August 16, these 4 had produced 8, of which all but 2 were 

 removed, et cetera. 



The last column of table 32 gives the total number of fissions 

 undergone by the line in question, up to September 7, or to its 

 death. As the lines of set K were all obviously vigorous, only 

 five were kept under observation till September 7, when the last 

 line of set D 2 died out. 



To grasp the results, it will be best to examine first the facts 

 for set A', which had lived in mass cultures since May 15, and 

 had conjugated June 3. In this case, as will be observed, all the 

 ten lines flourished well. Number 4 was lost by accident August 

 28, and numbers 3, 5, 7 and 9 were discontinued September 3, 

 because the results were clear. 



New, compare with these the results given for the conjugants 

 and non-conjugants of August 10 (the depressed race) in sets D 1 

 and D 2. It is clear from the data of set D 1 that the conjugation 

 of August 10 has by no means restored this depressed series to the 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 14, NO. 3 



