_Nicotine_, C_{10}H_{14}N_{2}, the next simplest in formula of the alkaloids, is a tertiary base, that is, contains no replaceable hydrogen atoms in its molecule. It shows very close relations to pyridine. When nicotine vapor is passed through a red-hot tube, it yields essentially collidine, and, with this, some pyridine, picoline, lutidine, and gases such as hydrogen, marsh-gas, and ethylene. Heated with bromine water to 120°C. it decomposes into bromoform, carbon dioxide, nitrogen, and pyridine. When its alcoholic solution is treated with ferricyanide of potassium it is oxidized to dipyridine, C_{10}H_{10}N_{2}. Potassium permanganate, chromic or nitric acid oxidises it to nicotinic acid, C_{6}H_{5}NO_{2}, which is simply pyridine-carboxylic acid, C_{5}H_{4}N(COOH), and which, distilled over quick-lime, yields pyridine, C_{5}H_{5}N. Turning now to the non-volatile and oxygenized bases, we take up first the opium alkaloids. _Morphine_, C_{17}H_{19}NO_{3}, is a tertiary amine, and appears to contain a hydroxyl group like phenols, to which class of bodies it has some analogies, as is shown in its reaction with ferric chloride. Its meythl ester, which can be formed from it, is _codeine_, one of the accompanying alkaloids of opium. Besides the methyl derivative, however, others are possible, and several have been recently prepared, giving rise to a class of artificial alkaloids known as _codeines_. Morphine, rapidly distilled over zinc dust, yields phenanthren, trimethyl-amine, pyrrol, pyridine, quinoline, and other bases. The action of strong hydrocholoric acid upon morphine changes it into apomorphine, C_{17}H_{17}NO_{2}, by the withdrawal of a molecule of water. Ferricyanide of potassium and caustic soda solution change morphine into oxidimorphine, C_{34}H_{36}N_{2}O_{6}. When heated with strong potassium hydrate, it yields methylamine. _Narcotine_, another of the opium alkaloids, when heated with manganese dioxide and sulphuric acid, is oxidized and splits apart into opianic acid, C_{10}H_{10}O_{5}, and cotarnine, C_{12}H_{13}NO_{3}. This latter, 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.