We may now look at the question of the decomposing effect of reagents upon the alkaloids.  The means which have proved most efficacious in decomposing these bases are the action of oxidizing and reducing agents, of bromine, of organic iodides, of concentrated acids and alkalies, and of heat.

Taking up the volatile alkaloids, we find with regard to conine, first, that the action of methyl iodide shows it to be a secondary amine, that is, it restrains only one replaceable hydrogen atom of the original ammonia molecule.  Its formula is therefore C_{8}H_{16}NH.  From conine can be prepared methyl-conine, which also occurs in nature, and dimethyl-conine.  From this latter has been gotten a hydrocarbon, C_{8}H_{14}, conylene, homologous with acetylene, C_{2}H_{2}.  Conine, on oxidation, yields chiefly butyric acid, but among the products of oxidation has been found the pyridine carboxylic acid before referred to.  The formula of conine, C_{8}H_{17}N, shows it to be homologous with piperidine, C_{5}H_{11}N, a derivative of piperine, the alkaloid of pepper, to be spoken of later; and, just as piperidine is derived from pyridine by the action of reducing agents, so conine is probably derived from a propyl-pyridine.  The artificial alkaloid paraconine, isomeric with the natural conine, will be referred to later.

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 deg.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.