ioo Plant Genetics 



This would explain the peculiar breeding results 

 obtained by CORRENS. If this explanation is true 

 Mendel's law is not contradicted, for such a phenomenon 

 is entirely outside the field of that law. In fact, this 

 should perhaps not be regarded as inheritance at all 

 but as a case of reinfection. The albomaculata condi- 

 tion is not a true plant character; it is a pathological 

 state, not inherited as such, but the bacteria in the 

 cytoplasm of the egg reinfect the next generation. 



The conclusion therefore is that Mendel's law is not 

 contradicted by this phenomenon, but it introduces 

 entirely new possibilities of inheritance quite outside the 

 scope of Mendel's law. This conclusion is reached if 

 one accepts CORRENS' explanation, but this might well 

 be doubted. To state that albomaculata cytoplasm is 

 always infected and that the nuclei are always immune 

 is a bold assumption. If we assume, with some cytolo- 

 gists, that the nucleus consists entirely of chromatin and 

 that chromatin is immune to this disease this would 

 furnish the proper mechanism, but this is questionable. 

 Again, when it is claimed that no bacteria could enter 

 the egg with the male nucleus another rash assumption is 

 made. After all, the case of albomaculata may still 

 be regarded as a genuine case of non-Mendelian inherit- 

 ance of the type known as maternal inheritance. 



The other example of non-Mendelian inheritance to 

 which EMERSON and EAST referred is much more serious, 

 introducing somatic segregation, which is a very far- 

 reaching topic. When EMERSON and EAST made their 

 statement somatic segregation had been rarely observed, 

 there being really only one authentic case on record, 

 that is, the case of the common geranium (Pelargonium 



