IS quite as truly as the
octogenarian IS the same identity with the ovum from which he has been
developed. This process cannot stop short of the primordial cell,
which again will probably turn out to be but a brief resting-place. We
therefore prove each one of us to BE ACTUALLY the primordial cell which
never died nor dies, but has differentiated itself into the life of the
world, all living beings whatever, being one with it and members one of
another," "Life and Habit", 1878, page 86.) Nevertheless in the present
state of knowledge we are still as a rule quite unable to connect
cytological appearances with any genetic consequence and save in one
respect (obviously of extreme importance--to be spoken of later) the two
sets of phenomena might, for all we can see, be entirely distinct.

I cannot avoid attaching importance to this want of connection between
the nuclear phenomena and the features of bodily organisation. All
attempts to investigate Heredity by cytological means lie under
the disadvantage that it is the nuclear changes which can alone be
effectively observed. Important as they must surely be, I have never
been persuaded that the rest of the cell counts for nothing. What we
know of the behaviour and variability of chromosomes seems in my opinion
quite incompatible with the belief that they alone govern form, and are
the sole agents responsible in heredity. (This view is no doubt contrary
to the received opinion. I am however interested to see it lately
maintained by Driesch ("Science and Philosophy of the Organism", London,
1907, page 233), and from the recent observations of Godlewski it has
received distinct experimental support.)

If, then, progress was to be made in Genetics, work of a different kind
was required. To learn the laws of Heredity and Variation there is
no other way than that which Darwin himself followed, the direct
examination of the phenomena. A beginning could be made by collecting
fortuitous observations of this class, which have often thrown a
suggestive light, but such evidence can be at best but superficial and
some more penetrating instrument of research is required. This can only
be provided by actual experiments in breeding.

The truth of these general considerations was becoming gradually clear
to many of us when in 1900 Mendel's work was rediscovered. Segregation,
a phenomenon of the utmost novelty, was thus revealed. From that moment
not only in the problem of the origin of sp