H R R R R R H H / / / / \ / \ / N-H N-H N-H N-R N-R N-H \ \ \ \ / \ / \ H H R R R OH H OH Ammonia Primary Secondary Tertiary Quaternary Ammonium amine amine amine amine hydroxide The simple amines which occur in animal tissues are known as "ptomaines" and "leucomaines." The ptomaines are all decomposition products resulting from the putrefactive decay of proteins caused by moulds or bacteria. Some of these are highly toxic, producing the so-called "ptomaine-poisoning"; while others are wholly innocuous. They are all simple amines. Putrescine, di-amino butane, NH_{2}·CH_{2}·CH_{2}·CH_{2}·CH_{2}·NH_{2}, and cadaverine, di-amino pentane, HN_{2}·(CH_{2})_{5}·NH_{2}, are common non-toxic ptomaines, resulting from the decay of meat. Neurine, trimethyl-ethylene ammonium hydroxide, (CH_{3})_{3}(C_{2}H_{3})·NOH, is a violently poisonous ptomaine produced in the decay of fish. Amines of similar structure to these are occasionally found in living animal tissues. Such compounds are known as _leucomaines_, to distinguish them from the _ptomaines_, which are found only in dead material. Corresponding in structure and properties to these amines of animal origin, there is a series of basic substances, found in many plants, known as the _plant amines_. The following are common examples: =Trimethyl amine=, (CH_{3})_{3}N, is a very volatile compound, found in the flowers of several species of the Rose family, the leaves of certain weeds, etc. When crushed, these tissues give off a very fetid odor, which is due to this amine. =Choline=, =muscarine=, and =betaine= are plant amines which are closely related to each other and to neurine (the toxic ptomaine) in composition and structure, as shown in the following formulas: CH_{2}CH_{2}OH CH_{2}CHO / / (CH_{3})_{3}N (CH_{3})_{3}N \ \ OH OH Choline Muscarine CH_{2}CO CH=CH_{2} / / / (CH_{3})_{3}N / (CH_{3})_{3}N \ / \ O OH Betaine Neurine Choline and betaine are non-toxic; while muscarine and neurine are violent poisons.