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
acid, which is a quinoline-carboxylic acid, C_{9}H_{6}N(COOH),
cinchomeronic acid, which has just been stated to be a pyridine
dicarboxylic acid, and a pyridine tricarboxylic acid. When cinchonine is
treated with potassium hydrate, it is decomposed into quinoline and a
solid body, which on further treatment yields a liquid base,
C_{7}H_{9}N, which is probably lutidine. It has been found, moreover,
that both tetrahydroquinoline and dihydroquinoline, hydrogen addition
products of quinoline, are present. When cinchonine is distilled with
solid potassium hydrate, it yields pyrrol and bases of both the pyridine
and quinoline series.

_Cinchonidine_, when heated with potassium hydrate, yields quinoline
also, and with nitric acid the same products as cinchonine.

_Strychnine_ has been found to be a tertiary amine. When distilled with
potassium hydrate, quinoline is formed.

_Brucine_ is a tertiary diamine, that is, formed by substitution in a
double ammonia molecule. When distilled with potassium hydrate it yields
quinoline, lutidine, and two isomeric collidines.

The alkaloid _atropine_ has been quite thoroughly studied with results
of great interest. When heated with baryta-water or hydrochloric acid,