of genealogy. It is a step in the right direction:
but

(3) The present methods of genealogy are inadequate to support such a
claim. Its methods are still based mainly on the historical, legal and
social functions. A few of the faults of method in genealogy, which the
eugenist most deplores, are:

(a) The information which is of most value is exactly that which
genealogy ordinarily does not furnish. Dates of birth, death and
marriage of an ancestor are of interest, but of limited biological
importance. The facts about that ancestor which vitally concern his
living descendant are the facts of his character, physical and mental;
and these facts are given in very few genealogies.

[Illustration: LINE OF ASCENT THAT CARRIES THE FAMILY NAME

FIG. 40.--In some pedigrees, particularly those dealing with
antiquity, the only part known is the line of ascent which carries the
family name,--what animal breeders call the tail-male. In such cases it
is evident that from the point of view of a geneticist practically
nothing is known. How insignificant any single line of ascent is, by
comparison with the whole ancestry, even for a few generations, is
graphically shown by the above chart. It is assumed in this chart that
no cousin marriages took place.]

(b) Genealogies are commonly too incomplete to be of real value.
Sometimes they deal only with the direct male line of ascent--the line
that bears the family name, or what animal breeders call the tail-male.
In this case, it is not too much to say that they are nearly devoid of
genuine value. It is customary to imagine that there is some special
virtue inherent in that line of descent which carries the family name.
Some one remarks, for instance, to Mr. Jones that he seems to be fond of
the sea.

"Yes," he replies, "You know the Joneses have been sailors for many
generations."

But the small contribution of heredity made to an individual by the line
of descent carrying his family name, in comparison with the rest of his
ancestry, may be seen from Fig. 40.

Such incomplete pedigrees are rarely published nowadays, but in studying
historic characters, one frequently finds nothing more than the single
line of ascent in the family name. Fortunately, American genealogies
rarely go to this extreme, unless it be in the earliest generations; but
it is common enough for them to deal only with the direct ancestors of
the individual, omitting all brothers and sisters of those ancestors.