500 E. ELEANOR CAROTHERS 
of the paternal and maternal chromatin according to the law of 
chance. 
The large dyad, which I shall arbitrarily designate as bearing 
characters of the male line, even when transmitted by the female, 
must represent characters of her male ancestors, either on the 
paternal or the maternal side. In like manner, the small dyad 
must represent characters of the female line, though half the 
time contributed by the male and, consequently, bringing in 
characters of his female ancestors. In other words, so far as this 
one pair of chromosomes is concerned, the spermatozoa may 
contain the small chromosome carrying factors from the maternal 
grandmother or from the paternal grandmother, or it may contain 
the large chromosome carrying characters of the paternal grand- 
father or the maternal grandfather. Likewise, the ova after 
maturation may contain, by hypothesis, the large chromosome 
inherited from either the paternal or the maternal male lines, or 
the small from the maternal or the paternal female lines. Hight 
combinations are, then, possible for this pair, as shown in the 
accompanying diagram. The possible combinations with various 
numbers of chromosomes has been worked out by Sutton (’03, 
p. 234, et seq.),so that further work on this line is superfluous. 
However, it may be well to emphasize the fact that the 68,719, 
- 476,736 combinations which he has shown to he possible in the 
zygotes of organisms possessing 36 chromosomes in the somatic 
series is amply sufficient to account for all observed variations, 
without the assumption of any interchange of material between 
the chromosomes. 
The only question that remains to be considered is whether 
Mendelian phenomena are exceptional cases of heredity, or whether 
they represent the type form of all inheritance. Perhaps the 
strongest arguments against the latter view have been derived 
from blends, first crosses that breed true and mosaics. 
In regard to the first, Hatai (’11) has shown that the series 
obtained from the square of the binomial (X?+2XY-+Y?)= 
expresses the distribution of determinates for both Mendelian and 
blended inheritance, and that therefore the latter may be 
