H. 10.--Pliny's picture has the interest of having been drawn almost
at the final disappearance of Druidism from the Roman world. For some
reason it was supposed to be, like Christianity, peculiarly opposed
to the genius of Roman civilization, and never came to be numbered
amongst the _religiones licitae_ of the Empire. Augustus forbade the
practice of it to Roman citizens,[61] Tiberius wholly suppressed it in
Gaul,[62] and, in conquering Britain, Claudius crushed it with a
hand of iron. Few pictures in the early history of Britain are more
familiar than the final extirpation of the last of the Druids, when
their sacred island of Mona (Anglesey) was stormed by the Roman
legionaries, and priests and priestesses perished _en masse_ in
the flames of their own altars.[63] Their desperate resistance was
doubtless due to the fact that Rome was the declared and mortal
enemy of their faith. So baneful, indeed, did Druidism come to be
considered, that to hold even with the least of its superstitions
was treated at Rome as a capital offence. Pliny tells us of a Roman
knight, of Gallic birth, who was put to death by Claudius for no other
reason than that of being in possession of a certain stone called
by the Druids a "snake's egg," and supposed to bring good luck in
law-suits.[64]

H. 11.--This stone Pliny himself had seen, and describes it (in his
chapter on the use of eggs) as being like a medium-sized apple, having
a cartilaginous shell covered with small processes like the discs
on the arms of an octopus. This can scarcely have been, as most
commentators suppose, the shell of an echinus (with which Pliny was
well acquainted), even if fossil. His description rather seems to
point to some fossil covered with _ostrea sigillina_, such as are
common in British green-sands. He adds an account of the Druidical
view of its production, how it is the solidified poison of a number of