by careful oxidation, yields apophyllenic acid, C_{8}H_{7}NO_{4}, and
this, on heating with hydrochloric acid to 240° C., yields
pyridine-dicarboxylic acid, C_{5}H_{9}N(COOH)_{2}. The base cotarnine
also results from the prolonged heating of narcotine with water alone.
In this case, instead of opianic acid, its reduction product meconine,
C_{10}H_{10}O_{4}, is produced.

_Meconic acid_, C_{7}H_{4}O_{7}, which is found in opium in combination
with the different bases, has also been investigated. By acting upon
meconic acid with ammonia, comenamic acid is formed, and this latter,
when heated with zinc dust, yields pyridine.

If we go now to the cinchona alkaloids, we meet with exceedingly
interesting results. _Quinine_, C_{20}H_{24}N_{2}O_{2}, when carefully
oxidized with chromic acid or potassium permanganate, yields a series of
products. First is formed quitenine, C_{19}H_{22}N_{2}O_{4}, a weak
base, then quininic acid, C_{11}H_{9}NO_{3}, then the so-called
oxycinchomeronic acid, C_{8}H_{5}N0_{6}, and finally cinchomeronic acid,
C_{7}H_{6}NO_{4}. Now the two acids last mentioned are simple
substitution products of pyridine, oxycinchomeronic acid being a
pyridine-dicarboxylic acid, C_{5}H_{2}N(COOH)_{3}, and cinchomeronic
acid, a pyridine-dicarboxylic acid, C_{5}H_{3}N(COOH)_{2}. When
distilled with potassium hydrate, quinine yields quinoline and its
homologues. The alkaloid has been shown to be a tertiary base.

_Quinidine_ yields with chromic acid the same decomposition products as
quinine.

_Cinchonine_, C_{19}H_{22}N_{2}O, the second most important alkaloid of
these barks, when oxidized with potassium permanganate, yields cinchonic