TJie InJieritauce of Acquired Characters 21 



have succeeded not only in building \i\) a high resistance 

 to typhoid in these female rabbits themselves, but in 

 securing from them progeny with a high resistance. In 

 fact, rabbits of the third generation have still shown a 

 high immunity which could have come only from their 

 grandmothers. The likelihood, however, is that this 

 immunity is not passed on through the germ cell itself, 

 but is "reacquired" by offspring while in utero, and 

 nourished by the blood stream of the mother. This, of 

 course, would again be merely a case of ''transmission" 

 rather than true inheritance. The passing on of such 

 an acquired immunity from the male parent to the pro- 

 geny would constitute a convincing demonstration of 

 inheritance of acquired characters, but such a demon- 

 stration has not as yet been made. 



. It is suspected that a situation similar to the foregoing exists 

 also in man. Racial immunity is believed by some medical men 

 to have been built up not only through a "natural selection" of 

 immune types, but from the passing on from mother to offspring 

 of acquired immunity. 



There is one fairly well known case of this sort in the 

 plant kingdom. Bolley (4) 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 sub- 

 jected to disease attack. He took a ])ure-pedigreed 

 strain of flax which had come original 1>' from a single 

 non-resisting seed. This was planted in slightly ''sick" 

 soil, that is, soil infected with the wilt-i)r()(lucing organ- 

 ism. Most of the individuals died, 1)ut ''a few scrubs" 

 survived. He then planted seeds from these in slightl\- 

 "sicker" soil than before, and thus, by gradually work- 



