126 



GENETIC VARIATIONS 



that have passed out into the cytoplasm and there interact 

 with each other and with other things ? 



On this point the investigator Jollos, to whom is due so 

 much of our knowledge on the genetics of these organisms, 



B 



Figure 21. Diagram of the disintegration of the macronucleus in 

 Paramecium. At A are seen both micronucleus and macronucleus. At 

 B, the macronucleus has broken into pieces, which are being absorbed 

 by the cytoplasm. 



has promulgated a widely known theory, according to which 

 none of these environmental modifications affect the reserve 

 genie materials in the micronucleus; they are held to be 

 limited to the genie materials of the macronucleus or of the 

 cytoplasm. For he assumes that any modifications of the genie 

 materials of the micronucleus would be permanent, since the 

 micronucleus is never lost. Since the acquired characters are 

 as a rule not completely permanent, but disappear or are 

 exchanged for others if the animals are kept for a sufficiently 



