334 READINGS IN EVOLUTION, GENETICS, AND EUGENICS 
the most conclusive demonstration that the hereditary character- 
istics of the transplanted ova are in no wise changed by the foster 
mother. They removed the ovary from a pure black guinea-pig and 
put it in the place of the ovary of a pure white animal. After recover- 
ing from the operation this white female with the “black” ovary was 
bred to a pure white male. Three litters of offspring from these 
parents were all pure black. Although both parents were pure white 
all the offspring of the Fz generation were black because they came 
from ‘“‘black” eggs and black is dominant over white. The fact that 
these “black” eggs developed in the body of a white female did not in 
the least change their hereditary constitution. 
Dominants and recessives remain pure.—A still more intimate 
union takes place when the dominant and recessive characters come 
together in any zygote. These characters, or rather the factors which 
determine them, may be intimately associated in every cell of the 
organism throughout an entire generation and yet we may get a clean 
separation of these characters in the next generation; in many cases 
neither the dominant nor the recessive character has been at all modi- 
fied by its most intimate association with the other. 
Climatic effects not inherited.—A striking instance of the purely 
temporary effect of the environment and of the long persistence of 
hereditary constitution amidst new environmental conditions, which 
have greatly changed the appearance of the developed organisms, is 
found in the case of alpine plants. Niégeli says that such plants, which 
have preserved the characters of high mountain plants since the ice 
age, lose these characters perfectly during their first summer in the 
lowlands. 
Summary.—If acquired characters were really inherited we should 
expect to find many positive evidences of this instead of a few sporadic 
and doubtful cases. In particular why do we not find in plant or 
animal grafting that the influence of the stock changes the hereditary 
potencies of the graft? Why do we not find that transplanted ovaries 
show the influence of the foster mother as Guthrie supposed—a thing 
which has been disproved by Castle? Why do dominant and recessive 
characters remain pure, even after their intimate union in a hybrid, so 
that pure dominants and pure recessives may be obtained in subse- 
quent generations from this mixture? Why does every child have to 
learn anew what his parents learned so laboriously before him? Even 
the strongest defenders of the inheritance of acquired characters are 
constrained to admit that it occurs only sporadically and excep- 
tionally. 
