PRESIDENT’S ADDRESS. 9 
of a part only of the soma, give hints of curious complications, and 
suggest that in plants at least the interrelations between soma and 
gamete may be far less simple than we have supposed. Nevertheless, 
speaking generally, we see nothing to indicate that qualitative characters 
descend, whether in plants or animals, according to systems which 
are incapable of factorial representation. 
The body of evidence accumulated by this method of analysis is 
now very large, and is still growing fast by the labours of many workers. 
Progress is also beginning along many novel and curious lines. The 
details are too technical for inclusion here. Suffice it to say that not 
only have we proof that segregation affects a vast range of characteris- 
tics, but in the course of our analysis phenomena of most unexpected 
kinds have been encountered. Some of these things twenty years ago 
must have seemed inconceivable. For example, the two sets of sex 
organs, male and female, of the same plant may not be carrying the 
same characteristics ; in some animals characteristics, quite independent 
of sex, may be distributed solely or predominantly to one sex; in 
certain species the male may be breeding true to its own type, while 
the female is permanently mongrel, throwing off eggs of a distinct 
variety in addition to those of its own type; characteristics, essentially 
independent, may be associated in special combinations which are 
largely retained in the next generation, so that among the grand- 
children there is numerical preponderance of those combinations which 
existed in the grandparents—a discovery which introduces us to a new 
phenomenon of polarity in the onganism. 
We are accustomed to the fact that the fertilised egg has a polarity, 
a front and hind end for example; but we have now to recognise that it, 
or the primitive germinal cells formed from it, may have another 
polarity shown in the groupings of the parental elements. Iam entirely 
sceptical as to the occurrence of segregation solely in the maturation of 
the germ-cells,* preferring at present to regard it as a special case of 
that patchwork condition we see in so many plants. These mosaics 
may break up, emitting bud-sports at various cell-divisions, and I 
suspect that the great regularity seen in the F, ratios of the cereals, for 
example, is a consequence of very late segregation, whereas the exces- 
sive irregularity found in other cases may be taken to indicate that 
segregation can happen at earlier stages of differentiation. 
The paradoxical descent of colour-blindness and other sex-limited 
conditions—formerly regarded as an inscrutable caprice of nature—has 
been represented with approximate correctness, and we already know 
something as to the way, or, perhaps, I should say ways, in which the 
“The fact that in certain plants the male and female organs respectively 
carry distinct factors may be quoted as almost decisively negativing the sug- 
gestion that segregation is confined to the reduction division, 
