Inheritance of Acquired Characters 23 



and eKminated from consideration. Certain parts of 

 this investigation have been carried on frequently and 

 satisfactorily and the whole investigation has been tried, 

 but under poorly controlled conditions. It remains, 

 therefore, to conduct the entire investigation under 

 proper conditions before one can reach any reliable 

 conclusion in reference to the inheritance of acquired 

 characters by plants. 



Another possible illustration of the inheritance of 

 responses to environmental conditions may be obtained 

 from the work of Bolley (i) on flax. The resistance of 

 a plant to a given disease is regarded as a character 

 pecuUar to certain strains and transmitted as a very 

 definite factor in Mendelian inheritance. Bolley claims 

 that he can get a resistant strain of flax from almost any 

 known variety. According to him the resisting ability 

 increases from generation to generation, if the crop 

 is constantly subjected to disease attack. He took a 

 pure-pedigreed strain of flax which had come originally 

 from a single non-resisting seed. This was planted in 

 slightly "sick" soil, that is, soil infected with the wilt- 

 producing organism. Most of the individuals died, but 

 "a few scrubs" survived. He then planted seeds from 

 these in slightly "sicker" soil than before, and thus, 

 by gradually working his crop into sicker and sicker soil 

 in the later generations, he finally obtained a fully 

 resistant strain from the pure non-resistant strain with 

 which he started. Such a strain he says will not lose its 

 resistance if planted progressively in more infected soils. 



Bolley also found that if he added to the soil manure, 

 alkalies, etc., known to increase the disease by stimulat- 

 ing the fungus, he obtained a very few poorly developed 



