EFFECT OF CONJUGATION 293 



Abnormal individuals appear again and again in certain of the 

 lines derived from conjugants, while in others they do not appear 

 at all. The conditions which induce them are thus evidently 

 inherited from generation to generation in the fissions. As a 

 rule, a given abnormality is not inherited in its special form, but 

 only the tendency to produce abnormaUties of various sorts. 



Lines which show abnormaUties in structure commonly have a 

 slow rate of fission, are thin, succumb easily to unfavorable con- 

 ditions, and in general, appear to lack \'itality. Often they die 

 out after a number of generations. 



There are likewise found lines which show the thinness, slow 

 fission rate, and general lack of vitality, without structural 

 abnormalities. 



It appears probable that these abnormalities have a cytologi- 

 cal basis, and are due to irregularities in the nuclear processes 

 accompanying conjugation. A precise study is greatly needed, 

 as to the minute characteristics of these abnormalities, their 

 heritability, their experimental cause, and their cytological basis. 

 Such a study I hope will soon be made. 



The data obtained from this experiment, and presented in 

 table 29, will be analyzed in later papers with reference to the 

 problems of sexuality, and of uniparental and biparental inheri- 

 tance. 



We may summarize the results of this experiment, so far as 

 they bear on the problems now under consideration, as follows: 



Conjugation decreases the rate of fission, causes a great increase 

 in variation in the fission rate, brings about many abnormalities, 

 and greatly increases the death rate. 



Experiment 2: April 7 to June 7, 1909 



* 

 This extensive and long continued experiment was the first 



one undertaken for comparing the fission-rate and vitality of 



animals that had conjugated and animals that had not. Owing 



to lack of experience the method of culture was not good, so 



that the mortality was very high; this makes the results less 



sharp and clear than in the experiment just described. The chief 



mistakes in culture were: (1) the culture fluid was not made up 



