114 THE ESSEX NATURALIST.
to be profane, the humble historian has to call attention to a
circumstance as remarkable from the standpoint of the naturalist,
and as important from that, of the economist, as the facts
adduced by Fontenelle and by Voltaire. However closely
particular strains of the various kinds of Cinchona bark may
agree as to the percentage of their total alkaloid-content, the
different kinds of Cinchona bark do not agree as regards the
proportion of quinine to the other alkaloids they contain. For
this reason the historian, though he has no record of the
particular kind of bark from which Pellatier and Caventou first
extracted quinine, can say that the bark they used was not
"grey bark" from Huanuco, since "grey bark," however rich
in alkaloids, contains little quinine. He can add that it is
unlikely that the bark they used was "red bark" from
Chimborazo, since in "red bark," however rich, only one-
third of the total alkaloid-content is quinine. He must con-
clude that it is improbable that they used "pale bark,"
since the "pale bark" of Loja, though three-fourths of the total
alkaloid-content is quinine, had, by 1820, become very scarce.
He therefore suggests that the bark they used may have been a
"yellow bark," since in the "yellow barks," which do not extend
beyond the northern frontier of Bolivia, five-sixths of the total
alkaloid-content may be quinine. As quinine is the alkaloid of
Cinchona bark most favoured by medicine, the chemist who
extracts that alkaloid can only afford to pay the exploiter or
cultivator of bark in terms of its quinine-content, and the
cultivator now can only expect to avoid loss if he restricts his
efforts to the growing of the richest strain of "yellow bark."
The fact that quinine found immediate favour in medical
practice led to widespread competitive activity in separating this
alkaloid from Cinchona bark. Among those who, almost from
the outset, took part in this enterprise were the members of the
house of Howards at Ilford, to whom humanity owes in conse-
quence a debt it is not within our power to assess, and of whom
the county of Essex has ample reason to be proud. But the
success of this and of kindred establishments elsewhere had
a serious effect on the Cinchona forests of the Andes. The
districts whence "red bark" and "yellow bark" were drawn
could not bear the strain, which was intensified because "grey
bark" was not suitable for the purpose and supplies of "pale