The Making of Species 
offspring. Or the D gamete from one parent 
may unite with a T gamete from the other 
parent, and the result will be a TD cross, but 
this, as we have seen, will grow up to look like 
a pure T, ze. will become a tall organism. 
Similarly, a T gamete from one parent may 
unite with a T gamete of the other, and produce 
a pure tall form, or it may unite with a D and 
produce a hybrid TD, which gives rise to a 
tall form. Thus the possible combinations of 
offspring are DD, DT, TD, TT, but all these 
three last contain the dominant T gamete, and 
so develop into tall offspring; therefore, ex 
hypothest, we shall have three tall forms pro- 
duced to one dwarf form, but of these three 
tall forms two are not pure, and do not breed 
true. Mendel’s experimental results accorded 
with what we should expect to obtain if the 
above explanation were correct. Hence the 
inference that there is such a splitting of the 
gametes in the sexual act seems a legitimate one. 
Mendel’s experiments are of great import- 
ance, for they give us some insight into the 
nature of the sexual act. But, as is usual 
in such cases, Mendel’s disciples have greatly 
exaggerated the value and importance of his 
work. It is necessary to bear in mind that 
Mendel’s results apply only to a _ limited 
number of cases—to what we may call balanced 
characters. In the case of characters which 
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