234 THE ESSEX NATURALIST.
authority on this subject, for the suggestion that a clue to the
"centre of origin" of a cultivated crop may be found in the
"centre of diversity" of forms of the plant concerned. If we
may judge from the details supplied in one of the appendices to
Dr. Hurry's work, the "centre of origin" of Woad cultivation
should be sought in or near Asia Minor, rather than in Europe.
This possibility is strengthened by a circumstance to which
Dr. Hurry has not alluded. He has traced the therapeutic use
of Woad back to the time of Hippocrates, five centuries before
our era began. Thanks to Mr. R. C. Thompson, we know now
that Woad is one of the drugs enumerated in the "Assyrian
Herbal," that it was used by the physicians of Nineveh much as
it was used by later Greek physicians; and that its Assyrian name,
uk-natum, indicates that it was "the source of a blue dye."
This may help Hebrew scholars to settle the debated question
as to the substance used in dyeing "the robe of the ephod all
of blue," of which we read in Exodus. As Dr. Hurry admits,
there is no positive proof that Woad was grown in Egypt for the
sake of its dye until the second century A.D., when the country
had become a Roman province. Yet the new fact adduced by
Mr. Thompson as regards Woad in Mesopotamia, lends colour to
Dr. Hurry's suggestion that the Indigo often alluded to in con-
nection with mummy cloths may have been derived from Woad.
We need not accept the view of Mr. Lucas that the Indigo
used by the ancient Egyptians was probably imported from
India, since we know now that they might equally readily have
obtained Indigo from Abyssinia, though we can agree with
Mr. Lucas that Indigo was "almost certainly not cultivated in
Ancient Egypt." It is, however, true that Indigo, as its name
suggests, was an Indian commodity. Whatever may have been
the mutual relationships of the three ancient cultures which
originated on the banks of the Indus, the Euphrates, and the Nile,
the existence of Indigo in India is sufficient to explain the fact
that the cultivation of Woad never passed from Mesopotamia to
India, as it eventually did from Mesopotamia to Egypt.
For the selection of a crop to illustrate the part man has played
in modifying the character and appearance of the plants concerned
we are indebted to Dr. Hurry. In the chapter which deals with
"Woad in Relation to Agriculture" he remarks that Wheat has
also been described as "a pillar of civilization." The high